Suspension element systems and methods

ABSTRACT

A damper assembly includes a tubular member including a sidewall and a shoulder. The damper assembly includes a rod and a piston coupled to the rod. A secondary piston has a second contact surface, an opposing second surface, an inner cylindrical face defining a central aperture that receives the rod, and an outer cylindrical face. The opposing second surface includes one or more surface grooves, extending between the inner cylindrical face and the outer cylindrical face along the opposing second surface, and one or more bypass orifices disposed about the body member. The bypass orifices extend along the inner cylindrical face between the second contact surface and the opposing second surface. The secondary piston defines a channel extending between the inner cylindrical face and an outer periphery of the body member. The channel and bypass orifices form a fluid flow path when the piston contacts the secondary piston.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation in part of U.S. application Ser. No.15/956,974, filed Apr. 19, 2018, which claims the benefit of U.S.Provisional Application No. 62/491,132, filed Apr. 27, 2017, and U.S.Provisional Application No. 62/491,971, filed Apr. 28, 2017, all ofwhich are incorporated herein by reference in their entireties. Thisapplication is also a continuation in part of U.S. application Ser. No.16/041,229, filed Jul. 20, 2018, which is a continuation of U.S.application Ser. No. 15/084,375, filed Mar. 29, 2016, now U.S. Pat. No.10,030,737, which is a continuation of U.S. application Ser. No.13/792,151, filed Mar. 10, 2013, now U.S. Pat. No. 9,303,715, all ofwhich are incorporated herein by reference in their entireties.

BACKGROUND

The present disclosure relates generally to the field of vehiclesuspension systems. More specifically, the present disclosure relates todampers used in independent suspension systems that facilitateindependent wheel movement as the vehicle encounters one or moreobstacles (e.g., uneven terrain, potholes, curbs, etc.).

SUMMARY

One implementation of the present disclosure is a damper assembly,according to some embodiments. The damper assembly includes a tubularmember including a sidewall and a cap at an end of the sidewall,according to some embodiments. In some embodiments, the sidewall and thecap define an inner volume. In some embodiments, the sidewall includes afirst portion and a second portion which define a shoulder. The damperassembly includes a rod extending within the inner volume, according tosome embodiments. In some embodiments, the damper assembly includes aprimary piston positioned within the inner volume and coupled to therod, the primary piston defining a first contact surface. The damperassembly further includes a secondary piston including a body memberhaving a second contact surface, an opposing second surface, an innercylindrical face defining a central aperture that receives the rod, andan outer cylindrical face, according to some embodiments. The opposingsecond surface includes one or more surface grooves disposed about thebody member, extending between the inner cylindrical face and the outercylindrical face along the opposing second surface, and one or morebypass orifices disposed about the body member, according to someembodiments. The bypass orifices extend along the inner cylindrical facebetween the second contact surface and the opposing second surface,according to some embodiments. In some embodiments, the secondary pistondefines a channel extending between the inner cylindrical face and anouter periphery of the body member. In some embodiments, the primarypiston and the secondary piston separate the inner volume into a firstworking chamber, a second working chamber, and a recoil chamber. In someembodiments, the damper assembly includes a resilient member disposedbetween the secondary piston and the cap and thereby positioned to biasthe secondary piston into engagement with the shoulder. In someembodiments, the first contact surface and the channel are configured tocooperatively define a flow conduit upon engagement between the primarypiston and the secondary piston. In some embodiments, the second contactsurface is configured to engage the first contact surface such that anopen flow path is formed from the recoil chamber through the centralaperture and the flow conduit upon engagement between the primary pistonand the secondary piston.

Another implementation of the present disclosure is a damper assembly,according to some embodiments. In some embodiments, the damper assemblyincludes a housing, a primary piston, a limiter piston, a resilientmember, and a rod. In some embodiments, the housing has an end cap anddefines an inner volume. In some embodiments, the housing includes afirst portion and a second portion. In some embodiments, the transitionbetween the first portion and the second portion defines a shoulder. Insome embodiments, the primary piston is positioned within the housing.In some embodiments, the limiter is positioned between the primarypiston and the end cap. In some embodiments, the limiter includes adamper piston including a body member having a contact surface, an innercylindrical face that defines an aperture through a central portion ofthe body member, an outer cylindrical face, and one or more bypassorifices. In some embodiments, the opposing second surface includes oneor more surface grooves disposed about the body member, extendingbetween the inner cylindrical face and the outer cylindrical face alongthe opposing second surface. In some embodiments, the one or more bypassorifices are disposed about the body member. In some embodiments, thebypass orifices extend along the inner cylindrical face between thesecond contact surface and the opposing second surface. In someembodiments, the primary piston and the damper piston separate the innervolume into a first working chamber, a second working chamber, and arecoil chamber. In some embodiments, the resilient member is disposedwithin the recoil chamber, between the opposing second surface of thedamper piston and the end cap. In some embodiments, the resilient memberis thereby positioned to bias the damper piston into engagement with theshoulder. In some embodiments, the rod is coupled to the primary pistonand extends through the aperture defined by the damper piston. In someembodiments, the damper piston defines a channel extending laterallyoutward from the inner cylindrical face across the contact surface to anouter periphery of the body member. In some embodiments, the primarypiston and the channel are configured to cooperatively define a firstflow conduit upon engagement between the primary piston and the damperpiston. In some embodiments, an outer surface of the rod and the innercylindrical face of the damper piston define a second flow conduit. Insome embodiments, the first flow conduit and the second flow conduitcooperate to define an open flow path from the recoil chamber.

Another implementation of the present disclosure is a damper assembly.The damper assembly includes a housing, a primary piston, a limiter, aresilient member and a rod, according to some embodiments. In someembodiments, the housing has an end cap, and the housing and the end capdefine an inner volume. In some embodiments, the housing includes afirst portion and a second portion which define a shoulder. In someembodiments, the primary piston is positioned within the housing. Insome embodiments, the limiter is positioned between the primary pistonand the end cap and include a damper piston. In some embodiments, thedamper piston includes a body member having a contact surface, an innercylindrical face, an outer cylindrical face, an opposing second surface,and one of more bypass orifices. In some embodiments, the innercylindrical face defines an aperture through a central portion of thebody member. In some embodiments, the opposing second surface includesone or more surface grooves disposed about the body member, extendingbetween the inner cylindrical face and the outer cylindrical face alongthe opposing second surface. In some embodiments, the one or more bypassorifices are circumferentially disposed about the body member. In someembodiments, the bypass orifices extend along the inner cylindrical facebetween the second contact surface and the opposing contact surface. Insome embodiments, the primary piston and the damper piston separate theinner volume into a first working chamber, a second working chamber anda recoil chamber. In some embodiments, the resilient member is disposedwithin the recoil chamber, between the opposing second surface of thedamper piston and the end cap. In some embodiments, the resilient memberis thereby positioned to bias the damper piston into engagement with theshoulder. In some embodiments, the rod is coupled to the primary pistonand extends through the aperture defined by the damper piston. In someembodiments, the damper piston defines a channel extending laterallyoutward from the inner cylindrical face across the contact surface to anouter periphery of the body member. In some embodiments, the damperpiston defines an inner channel within the inner cylindrical facebetween the contact surface and the opposing second surface. In someembodiments, the primary piston and the channel are configured tocooperatively define a flow conduit upon engagement between the primarypiston and the damper piston. In some embodiments, the flow conduit andthe inner channel cooperate to define an open flow path from the recoilchamber.

The invention is capable of other embodiments and of being carried outin various ways. Alternative exemplary embodiments relate to otherfeatures and combinations of features as may be recited in the claim.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-2 are perspective views of axle assemblies, according toalternative embodiments.

FIG. 3A is a side view of a suspension element, according to anexemplary embodiment.

FIG. 3B is a sectional view of the suspension element of FIG. 3A.

FIG. 4 is a sectional view of a suspension element, according to analternative embodiment.

FIG. 5 is an elevation view of a damper assembly having a limiter thatdissipates energy, according to an exemplary embodiment.

FIGS. 6A-6D are elevation views of the damper assembly of FIG. 5 invarious stages of compression.

FIG. 7A is an elevation view of a damper assembly, according to anexemplary embodiment.

FIG. 7B is an elevation view of a secondary piston of a damper,according to an exemplary embodiment.

FIG. 7C is a top view of a secondary piston of a damper, according to anexemplary embodiment.

FIG. 8 is a top view of a secondary piston of a damper, according to anexemplary embodiment.

FIG. 9A is a side view of a suspension element, according to analternative embodiment.

FIG. 9B is a top view of the suspension element of FIG. 9A.

FIG. 9C is a sectional view of the suspension element of FIG. 9A.

FIG. 9D is a detailed view of an upper mount of the suspension elementof FIG. 9C.

FIG. 9E is sectional view of the suspension element of FIG. 9B.

FIG. 9F is another sectional view of the suspension element of FIG. 9B.

FIG. 10A is an elevated side view of a suspension element and a mountingstructure, according to an exemplary embodiment.

FIG. 10B is a lower view of the suspension element and mountingstructure of FIG. 10A.

FIG. 10C is an elevated view of the mounting structure of FIG. 10A.

FIG. 10D is a lower view of the suspension element and mountingstructure of FIG. 10A.

FIG. 10E is a side view of the suspension element and mounting structureof FIG. 10A.

FIG. 10F is an exploded view of the mounting structure of FIG. 10A.

FIG. 10G is a side view of the mounting structure of FIG. 10A.

FIG. 10H is a lower view of the mounting structure of FIG. 10A.

FIG. 10I is a side view of the mounting structure of FIG. 10A.

FIG. 11A is a side view of a main tube and cap of a suspension element,according to an exemplary embodiment.

FIG. 11B is an exploded view of the main tube and cap of the suspensionelement of FIG. 11A.

FIG. 12 is a side view of a suspension element and an upper mount,according to an exemplary embodiment.

FIG. 13 is an elevation view of a secondary piston of a damper,according to an exemplary embodiment.

FIG. 14 is a bottom elevation view of the secondary piston of FIG. 13.

FIG. 15A is a top view of the secondary piston of FIG. 13.

FIG. 15B is a top view of a secondary piston, according to an exemplaryembodiment.

FIG. 16 is a diagram illustrating a flow path of fluid of the damperassembly of FIG. 5.

FIG. 17 is a sectional view of a damper assembly in a first position,according to an exemplary embodiment.

FIG. 18 is a sectional view of the damper assembly of FIG. 17 in asecond position.

FIG. 19 is a sectional view of the damper assembly of FIG. 17 in a thirdposition.

FIG. 20 is a top sectional view of the damper assembly of FIG. 17.

FIG. 21 is an elevated sectional view of the damper assembly of FIG. 17.

DETAILED DESCRIPTION

Before turning to the figures, which illustrate the exemplaryembodiments in detail, it should be understood that the presentapplication is not limited to the details or methodology set forth inthe description or illustrated in the figures. It should also beunderstood that the terminology is for the purpose of description onlyand should not be regarded as limiting.

According to an exemplary embodiment, a vehicle includes a bodysupported by a suspension system. In some embodiments, the vehicle is amilitary vehicle. In other embodiments, the vehicle is a utilityvehicle, such as a fire truck, a tractor, construction equipment, or asport utility vehicle. The vehicle may be configured for operation onboth paved and rough, off-road terrain. The suspension system may becorrespondingly configured to support the weight of the vehicle whileproviding comfortable ride quality on both paved and rough, off-roadterrain. In some embodiments, the suspension system is configured tochange the ride height of the vehicle by lifting or lowering the body ofthe vehicle with respect to the ground.

Referring to FIGS. 1-2, an axle assembly is configured for use with thevehicle. According to the exemplary embodiment shown in FIG. 1, an axleassembly 10 includes a differential 12 connected to half shafts 14,which are each connected to a wheel end assembly 16. Alternatively, eachwheel end assembly 16 includes a prime mover (e.g., the axle assembly 10includes electric motors that each drive one wheel). Alternatively, thewheel end assembly 16 may be implemented on a non-driven axle (e.g., anaxle that includes or does not include a differential, half shaft, drivemotor, or other component configured to provide a motive force, etc.);for example, as shown in FIG. 2. As shown in FIGS. 1-2, the wheel endassembly 16 is at least partially controlled (e.g., supported) by asuspension system 18, which includes a suspension element, shown asintegrated spring damper 20, an upper support arm 24, and a lowersupport arm 26 coupling the wheel end assembly 16 to the vehicle body orpart thereof (e.g., chassis, side plate, hull, etc.).

As shown in FIG. 1, the differential 12 is configured to be connectedwith a drive shaft of the vehicle, receiving rotational energy from aprime mover of the vehicle, such as a diesel engine. The differential 12allocates torque provided by the prime mover between half shafts 14 ofthe axle assembly 10. The half shafts 14 deliver the rotational energyto the wheel end assemblies 16 of the axle assembly 10. The wheel endassemblies 16 may include brakes (e.g., disc brakes, drum brakes, etc.),gear reductions, steering components, wheel hubs, wheels, and otherfeatures. As shown in FIG. 2, the wheel end assemblies 16 include discbrakes. As the vehicle travels over uneven terrain, the upper and lowersupport arms 24, 26 at least partially guide the movement of each wheelend assembly 16, and a stopper, shown as cushion 28 provides an upperbound for movement of the wheel end assembly 16.

As shown in FIG. 2, the suspension system 18 includes various componentsconfigured to improve performance of the vehicle. The suspension system18 may also include various auxiliary components (not shown) such as ahigh-pressure gas pump coupled to a gas spring, a plurality ofhigh-pressure gas pumps each coupled to separate gas springs, or fewergas pumps than gas springs. In some embodiments, at least one of thesuspension components receive and provide a fluid (e.g., gas, hydraulicfluid) to lift or lower the body of the vehicle with respect to theground thereby changing the ride height of the vehicle.

According to the exemplary embodiment shown in FIGS. 3A-3B, anintegrated spring damper 100 is configured to act as a damper (e.g., ahydraulic damper) and a spring (e.g., a high pressure gas spring)simultaneously. The integrated spring damper 100 includes a main body102 (e.g., cylinder, housing, base, etc.). In one embodiment, main body102 is tubular. The ends of the main body 102 are closed by a cap 104and a barrier 106 to define an internal volume. The internal volume ofthe main body 102 is separated into a central chamber and an annular,outer chamber by an inner tube 110 that extends from the cap 104 to thebarrier 106. The end of the inner tube 110 proximate to the barrier 106is closed with a cap 112. The cap 112 may be generally aligned with thebarrier 106 (e.g., received in a central opening 114 in the barrier106). The integrated spring damper 100 further includes a tubular (e.g.,cylindrical, etc.) element, shown as main tube 116. In one embodiment,main tube 116 is tubular and defines an inner volume. The main tube 116is received in the annular chamber of the internal volume of the mainbody 102. The main tube 116 is configured to translate with respect tothe main body 102. According to an exemplary embodiment, the main tube116 has an inner diameter that is approximately equal to the outerdiameter of the inner tube 110 such that the inner tube 110 is receivedin the main tube 116 when the main tube 116 is disposed within theinternal volume of the main body 102. The distal end of the main tube116 is closed by a cap 118. The cap 104, barrier 106, cap 112, and cap118 may be coupled to the respective components with a threadedconnection or with another coupling mechanism (e.g., welding, brazing,interference fit, etc.).

According to an exemplary embodiment, the integrated spring damper 100includes a first eyelet 120 and a second eyelet 122 with which theintegrated spring damper 100 is coupled to an axle assembly. Accordingto an exemplary embodiment, the integrated spring damper 100 is coupledon one end (e.g., with the first eyelet 120) to a moveable member of theaxle assembly (e.g., an upper support arm, a lower support arm, etc.)and on the other end (e.g., with the second eyelet 122) to the vehicle,vehicle structural element, vehicle body, or part thereof (e.g.,chassis, side plate, hull). According to an exemplary embodiment, thefirst eyelet 120 and the second eyelet are integrally formed with thecap 104 and the cap 118, respectively.

A main piston 124 is disposed in the outer annular chamber definedbetween the main body 102 and the inner tube 110. The main piston 124 iscoupled to the main tube 116 and extends to an inner surface of the mainbody 102. The main piston 124 separates the outer annular chamber intofirst annular chamber 126 and a second annular chamber 128. When themain tube 116 translates relative to the main body 102, the main piston124 changes the volume of the first annular chamber 126 and the secondannular chamber 128. A dividing piston 130 (e.g., floating piston) isdisposed in the inner chamber defined by the inner tube 110. Thedividing piston 130 slidably engages the inner tube 110. The dividingpiston 130 separates the inner chamber into first inner chamber 132 anda second inner chamber 134. The pistons 124 and 130 may be coupled tothe sidewalls of the main body 102 and the inner tube 110 with a seal orother interfacing member (e.g., ring, wear band, guide ring, wear ring,etc.).

The first annular chamber 126, the second annular chamber 128, and thefirst inner chamber 132 contain a generally non-compressible fluid. Inone embodiment, the first annular chamber 126, the second annularchamber 128, and the first inner chamber 132 are hydraulic chambersconfigured to contain a hydraulic fluid therein (e.g., water, hydraulicoil, etc.). The first inner chamber 132 is in fluid communication withthe first annular chamber 126 through apertures 136 in the inner tube110. The fluid may flow between the first annular chamber 126 and thesecond annular chamber 128 through a passage 142 (e.g., conduit, bore,etc.) in a bypass manifold 140. According to an exemplary embodiment,the bypass manifold 140 is a structure coupled (e.g., bolted) to theside of the main body 102 and the passage 142 is in fluid communicationwith the first annular chamber 126 through an aperture 144 in the mainbody 102 and with the second annular chamber 128 through an aperture 146in the main body 102. Providing the bypass manifold 140 as a separatecomponent coupled to the exterior of the main body 102 allows the bypassmanifold 140 to be replaced to vary the behavior of the integratedspring damper 100, such as by changing the valving or adding optionalfeatures (e.g., position dependency).

The flow of fluid through the passage 142 is controlled by a flowcontrol device 148. According to an exemplary embodiment, the flowcontrol device 148 is a disk valve disposed within the bypass manifold140 along the passage 142. In other embodiments, the flow control device148 may be another device, such as a pop off valve, or an orifice. Inother embodiments, the flow control device remotely positioned but influid communication with the first annular chamber 126 and the secondannular chamber 128.

The second inner chamber 134 contains a generally compressible fluidthat may include (e.g., at least 90%, at least 95%) an inert gas such asnitrogen, argon, or helium, among others. The second inner chamber 134is in fluid communication with the internal volume 150 of the main tube116 through apertures 152 in the cap 112. In some embodiments, theinternal volume 150 of the main tube 116 is in fluid communication withexternal devices, such as one or more reservoirs (e.g., centralreservoir, tank), an accumulator, or device allowing the pressure of thegas to be adjusted. The pressure of the gas may be adjusted by removingor adding a volume of gas to adjust the suspension ride height.

When the integrated spring damper 100 is compressed or extended, themain tube 116 translates relative to the main body 102. The gas held inthe second inner chamber 134 compresses or expands in response torelative movement between the main tube 116 and the dividing piston 130,which may remain relatively stationary but transmit pressure variationsbetween the incompressible hydraulic fluid in the first inner chamber132 and the compressible fluid in second inner chamber 134. The gas inthe second inner chamber 134 resists compression, providing a force thatis a function of the compressibility of the gas, the area of the piston,the volume and geometry of the chamber, and the current state (e.g.,initial pressure) of the gas, among other factors. The receipt ofpotential energy as the gas is compressed, storage of potential energy,and release of potential energy as the gas expands provide a springfunction for the integrated spring damper 100.

Movement of the main tube 116 relative to the main body 102 translatesthe main piston 124, causing the volume of the first annular chamber 126and the second annular chamber 128 to vary. When the integrated springdamper 100 compresses, the volume of the first annular chamber 126decreases while the volume of the second annular chamber 128 increases.The fluid is forced from the first annular chamber 126 through thepassage 142 and past the flow control device 148 into the second annularchamber 128. The resistance to the flow of the fluid through the passageprovides a damping function for the integrated spring damper 100 that isindependent of the spring function. Movement of the main piston 124 alsochanges the pressure of the fluid within first inner chamber 132. Suchpressure variation imparts a force on a first side of the dividingpiston 130 that varies the pressure of the fluid within the second innerchamber 134.

Referring to FIG. 4, an integrated spring damper assembly 200 is shown,according to another exemplary embodiment. The integrated spring damperassembly 200 includes a tubular element (e.g., cylindrical, etc.), shownas main body 202 (e.g., cylinder, housing, base, etc.). The ends of themain body 202 are closed by a cap 204 and a barrier 206 to define aninternal volume. The integrated spring damper assembly 200 furtherincludes a tubular element (e.g., cylindrical, etc.), shown as main tube216. The main tube 216 is received in the internal volume of the mainbody 202. The main tube 216 is configured to translate with respect tothe main body 202. The distal end of the main tube 216 is closed by acap 218. The cap 204, barrier 206, and cap 218 may be coupled to therespective components with a threaded connection or with anothercoupling mechanism (e.g., welding, brazing, interference fit, etc.).

According to an exemplary embodiment, the integrated spring damperassembly 200 includes a first eyelet 220 and a second eyelet 222 withwhich the integrated spring damper assembly 200 is coupled to an axleassembly. According to an exemplary embodiment, the integrated springdamper assembly 200 is coupled on one end (e.g., with the first eyelet220) to a moveable member of the axle assembly (e.g., an upper supportarm, a lower support arm, etc.) and on the other end (e.g., with thesecond eyelet 222) to the vehicle, vehicle structural element, vehiclebody, or part thereof (e.g., chassis, side plate, hull). According to anexemplary embodiment, the first eyelet 220 and the second eyelet 222 areintegrally formed with the cap 204 and the cap 218, respectively.

A main piston 224 is disposed in the internal volume of the main body202. The main piston 224 is coupled to the main tube 216 and slidablyengages the main body 202. The main piston 224 separates the internalvolume into a first chamber 226 (e.g., compression chamber) and a secondchamber 228 (e.g., extension chamber). The first chamber 226 is agenerally cylindrical chamber comprising the portion of the internalvolume of the main body 202 between the main piston 224 and the cap 204.The second chamber 228 is an annular chamber defined between the mainbody 202 and the main tube 216 and extends between the main piston 224and the barrier 206. When the main tube 216 translates relative to themain body 202, the main piston 224 changes the volume of the firstchamber 226 and the second chamber 228. A dividing piston 230 (e.g.,floating piston) is disposed in the main tube 216 and slidably engagesthe main tube 216. The dividing piston 230 separates the internal volumeof the main tube 216 into the first inner chamber 232 and a second innerchamber 234. According to an exemplary embodiment, the first innerchamber 232 is open to (i.e., in fluid communication with) the firstchamber 226.

A limiter, shown as recoil damper 236, is disposed within the internalvolume of the main body 202 between the main piston 224 and the barrier206. The recoil damper 236 is intended to reduce the risk of damage tothe main piston 224, barrier 206, the sidewall of main body 202, orstill another component of the integrated spring damper assembly 200 byreducing the forces imparted by the main piston 224 as it travels towardan end of stroke.

A recoil damper 236 dissipates energy thereby reducing the total energyof the integrated spring damper assembly 200. As the vehicle encountersa positive obstacle (e.g., a bump, a curb, etc.) or a negative obstacle(e.g., a depression, etc.), the main tube 216 moves relative to mainbody 202. Various factors including, among others, the speed of thevehicle, the weight of the vehicle, and the characteristics of theobstacle affect the energy imparted into the integrated spring damperassembly 200 by the obstacle. By way of example, main tube 216translates away from the cap 204 of first eyelet 220 as a wheel of thevehicle encounters a negative obstacle. It should be understood that themain tube 216 possesses kinetic energy that contributes to the totalenergy of integrated spring damper assembly 200. Interaction of therecoil damper 236 with the main piston 224 dissipates energy therebyreducing the total energy of the integrated spring damper assembly 200.Such dissipated energy does not increase the kinetic energy of main tube216 or main piston 224, according to an exemplary embodiment.

Referring to FIG. 5, a recoil damper 310 according to an exemplaryembodiment is shown. To illustrate the design and operation of therecoil damper 310, FIG. 5 shows the recoil damper 310 integrated with asuspension component, shown as damper assembly 300. According to theexemplary embodiment shown in FIG. 5, damper assembly 300 includes atubular element (e.g. cylindrical), shown as shaft 338, coupled to abody portion 304. As shown in FIG. 5, body portion 304 includes atubular (e.g., cylindrical) main body, shown as housing 314, thatincludes a first end 322 and a second end 324. An end cap 332 is coupledto first end 322 of housing 314. Housing 314 includes a sidewall thatdefines an inner volume. The shaft 338 translates within the innervolume between an extended position and a retracted position. Accordingto an exemplary embodiment, a main piston, shown as plunger 312, ispositioned within the inner volume of housing 314 and coupled to an endof shaft 338. A limiter, shown as recoil damper 310, is disposed withinthe inner volume of housing 314 between plunger 312 and end cap 332.Recoil damper 310 is intended to reduce the risk of damage to plunger312, end cap 332, the sidewall of housing 314, or still anothercomponent of damper assembly 300 by reducing the forces imparted byplunger 312 as it travels toward an end of stroke. Occupants within avehicle experience large impulse forces as plunger 312 contacts end cap332 or a component of the suspension system engages a hard stop. Recoildamper 310 reduces such impulse forces transmitted to occupants withinthe vehicle by dissipating a portion of the kinetic energy of plunger312 and shaft 338 (i.e., provide a supplemental damping force) as damperassembly 300 reaches an end of stroke (e.g., as the piston reaches arecoil end of stroke, as the piston reaches a jounce end of stroke,etc.). According to an exemplary embodiment, recoil damper 310 reducesthe forces imparted to occupants within the vehicle from 35,000 poundsto 20,000 pounds. The forces may be imparted due to the stored energyinside the spring returning the wheel end to the full rebound position.

As shown in FIG. 5, a plunger 312 separates the inner volume of ahousing 314 into a compression chamber 316 and an extension chamber 318.As shown in FIG. 5, housing 314 also defines a port, shown as flow port320. According to an exemplary embodiment, a fluid (e.g., hydraulic oil,water, a gas, etc.) is disposed within the inner volume of housing 314.As the plunger 312 moves toward a first end 322 of housing 314, thepressure of the fluid within extension chamber 318 increases. Accordingto an exemplary embodiment, the fluid within extension chamber 318 flowsoutward through flow port 320. External valves (e.g. shim valves, etc.)restrict the flow of fluid from flow port 320 and provide a base levelof damping forces. Such a base level of damping may vary based on thelocation, speed, or other characteristics of plunger 312. The damperassembly 300 shown in FIG. 5, provides a constant base level dampingforce as plunger 312 translates between the first end 322 and a secondend 324 of housing 314.

According to an exemplary embodiment, recoil damper 310 includes asecondary piston, shown as secondary plunger 326. As shown in FIG. 5,secondary plunger 326 is an annular member positioned within extensionchamber 318. Secondary plunger 326 includes a contact surface that isconfigured to engage plunger 312. An opposing surface of secondaryplunger 326 is separated from the contact surface by the thickness ofsecondary plunger 326. According to an exemplary embodiment, secondaryplunger 326 is coupled to an inner sidewall of housing 314 with a seal(e.g., ring, wear band, guide ring, wear ring, etc.), shown asinterfacing member 328. A recoil chamber 330 is formed by the volume ofextension chamber 318 located between secondary plunger 326 and end cap332.

As shown in FIG. 5, interfacing member 328 is a ring that has a circularcross-sectional shape. According to an alternative embodiment,interfacing member 328 may have a rectangular, square, polygonal, orstill other cross-sectional shape. The interfacing member 328 ismanufactured from a rigid material (e.g., a hard plastic, etc.).According to an exemplary embodiment, the rigid interfacing member 328prevents fluid flow between the inner sidewall of housing 314 andsecondary plunger 326. A rigid interfacing member 328 may also centersecondary plunger 326 within the bore of housing 314 thereby reducingthe likelihood of wear between an outer surface of secondary plunger 326and housing 314. According to an alternative embodiment, interfacingmember 328 is manufactured from another material (e.g., glass reinforcednylon, a nitrile rubber, etc.).

According to an exemplary embodiment, recoil damper 310 includes aresilient member, shown as return spring 334. As shown in FIG. 5, returnspring 334 extends between a first end that engages secondary plunger326 and a second end that engages end cap 332. Return spring 334 may bean interlaced wave spring (i.e., a flat wire compression spring), a coilspring, or another type of spring. Return spring 334 positions secondaryplunger 326 within housing 314. The spring force generated by returnspring 334 may overcome gravity (e.g., where damper assembly 300 ispositioned in a vehicle suspension system with secondary plunger 326above end cap 332) or may position secondary plunger 326 more quicklythan gravity alone (e.g., where damper assembly 300 is positioned in avehicle suspension system with secondary plunger 326 below end cap 332,as shown in FIG. 5). Return spring 334 is not intended to damp themovement of plunger 312, and return spring 334 may have a relativelysmall spring constant (e.g., less than 500 pounds per inch). Accordingto an alternative embodiment, recoil damper 310 does not include areturn spring 334. Such a recoil damper may reposition secondary plunger326 using gravity or an alternative device.

According to an exemplary embodiment, secondary plunger 326 defines achannel (i.e., track, depression, kerf, notch, opening, recess, slit,etc.), shown as damping groove 336. As shown in FIG. 5, damping groove336 extends radially outward across the contact surface of secondaryplunger 326, along an inner cylindrical face of secondary plunger 326,and along the opposing surface of secondary plunger 326. According to analternative embodiment, damping groove 336 extends only along thecontact surface of secondary plunger 326. According to still anotheralternative embodiment, damping groove 336 extends across the contactsurface and along the inner cylindrical face of secondary plunger 326.As shown in FIG. 5, secondary plunger 326 defines two damping grooves336. According to an alternative embodiment, secondary plunger 326defines more or fewer damping grooves 336. Damping groove 336 is sizedto provide particular flow characteristics. According to an exemplaryembodiment, the channel is defined along an axis extending radiallyoutward from a centerline of secondary plunger 326. According to analternative embodiment, the channel is curvilinear or irregularlyshaped. According to an exemplary embodiment, the channel has a squarecross-sectional shape in a plane that is normal to the axis extendingfrom the centerline of secondary plunger 326. According to analternative embodiment, the channel has another cross-sectional shape(e.g., rectangular, circular, semicircular, parabolic, etc.).

As shown in FIG. 5, plunger 312 defines a contact surface that engagesthe contact surface of secondary plunger 326. According to an exemplaryembodiment, the contact surface of plunger 312 and the contact surfaceof secondary plunger 326 are complementary (i.e., corresponding,matched, correlative, etc.) thereby reducing the likelihood thatpressurized fluid will seep between recoil chamber 330 and extensionchamber 318 across the contact surfaces of plunger 312 and secondaryplunger 326. According to an alternative embodiment, a seal ispositioned between plunger 312 and secondary plunger 326.

According to an exemplary embodiment, a shaft 338 extends through thesecondary plunger 326 and is connected to the plunger 312 (see FIG. 5).According to an alternative embodiment, a shaft does not extend throughsecondary plunger (not shown). In this alternative embodiment, a damperassembly may include a shaft that is reversed; for example, a shaft thatprojects toward a second end of a housing from a plunger. In thisalternative embodiment, a limiter (e.g., a recoil damper) may bepositioned between the plunger and an end cap of the housing. Thelimiter may provide supplemental damping forces as the plungerapproaches an end of a stroke (e.g., full compression). According to theexemplary embodiment shown in FIG. 5, plunger 312 and secondary plunger326 are disk shaped. According to an alternative embodiment, plunger 312and secondary plunger 326 have still another shape.

According to an exemplary embodiment, the various components of damperassembly 300 (e.g., the sidewall of housing 314, plunger 312, secondaryplunger 326, shaft 338, etc.) have a circular cross section. Accordingto an alternative embodiment, the various components of damper assembly300 may include a different cross-sectional shape (e.g., rectangular,square, hexagonal, etc.). While shown in FIG. 5 as having a particularlength, width, and thickness, it should be understood that thecomponents of damper assembly 300 may be otherwise sized (e.g., to suita particular application).

According to the exemplary embodiment shown in FIGS. 5-6D, plunger 312is actuatable within housing 314 from a first location that is offsetfrom secondary plunger 326 (e.g., the position shown in FIG. 5) to asecond position where the contact surface of plunger 312 engages with(i.e., contacts, interfaces with, etc.) the contact surface of secondaryplunger 326 (e.g., the position shown in FIG. 6A). As shown in FIG. 6A,plunger 312 translates within housing 314 along a direction of travel340. Such motion may occur, by way of example, as the damper assembly300 approaches an extension end of stroke (e.g., in a recoil motion). Asshown in FIG. 6A, plunger 312 moves along direction of travel 340 suchthat the contact surface of plunger 312 engages the contact surface ofsecondary plunger 326. As the contact surface of plunger 312 engages thecontact surface of secondary plunger 326, the damping groove 336 ofsecondary plunger 326 and the contact surface of plunger 312 form a flowconduit.

According to an alternative embodiment, plunger 312 defines a channel.The channel of plunger 312 may correspond to damping groove 336 ofplunger 312 such that the channel of plunger 312 and damping groove 336of secondary plunger 326 together form a flow conduit. In otherembodiments, the channel of plunger 312 does not correspond to dampinggroove 336 of plunger 312 such that a plurality of flow conduits areformed between the damping groove 336 and the contact surface of plunger312 and the channels of plunger 312 and the contact surface of secondaryplunger 326. According to another alternative embodiment, secondaryplunger 326 does not include damping groove 336, and a channel definedwithin plunger 312 and a contact surface of plunger 312 form the flowconduit.

As plunger 312 translates between the position shown in FIG. 6A to theposition shown in FIG. 6B, fluid flows from recoil chamber 330, betweensecondary plunger 326 and shaft 338, through the conduit defined bydamping groove 336 and the contact surface of plunger 312, through apassage between plunger 312 and the sidewall of housing 314, and intocompression chamber 342. According to an exemplary embodiment, theconduit restricts the flow of fluid from recoil chamber 330 therebydissipating energy and providing a supplemental damping force. Accordingto an exemplary embodiment, damping groove 336 is positioned to reducethe buildup of debris and maintain an unobstructed flow channel alongthe conduit formed by damping groove 336 and the contact surface ofplunger 312. Wear between components of damper assembly 300, oxidation,or still other conditions may generate debris in the fluid of damperassembly 300. As shown in FIGS. 5-6D, damping groove 336 is definedacross a contact surface of secondary plunger 326. Fluid flowing throughthe inner volume of housing 314 (e.g., due to translation of plunger 312within housing 314) flushes debris from damping groove 336. Suchflushing and the movement of shaft 338 relative to secondary plunger 326reduce the risk of debris obstructing the fluid flow path between recoilchamber 330 and compression chamber 342 (e.g., between an inner surfaceof secondary plunger 326 and an outer surface of shaft 338).

According to an exemplary embodiment, the amount of energy dissipatedand the supplemental damping forces provided by recoil damper 310 (e.g.,due to fluid flow through the conduit) is related to the shape ofdamping groove 336. According to an exemplary embodiment, fluid flowdoes not occur between secondary plunger 326 and the sidewall of housing314. Secondary plunger 326 and interfacing member 328 limit fluid flowbetween recoil chamber 330 and compression chamber 342 to a flow paththrough the conduit. Recoil damper 310 thereby generates a fluid flowpath through the conduit, and interfacing member 328 facilitatesdetermining the expected performance characteristics (e.g., the amountof energy dissipated, the supplemental damping forces provided, etc.) ofrecoil damper 310. Such performance characteristics may be tuned as afunction only of the features of damping groove 336, according to anexemplary embodiment. Limiting fluid from flowing between secondaryplunger 326 and an inner sidewall of housing 314 also provides morepredictable and uniform energy dissipation and supplemental dampingforces (i.e., additional flow paths may introduce additional variabilityinto the energy dissipated by a limiter).

Referring next to FIG. 6C, plunger 312 maintains engagement withsecondary plunger 326 and continues to translate along direction oftravel 340. According to an exemplary embodiment, the end cap 332 is ahard stop for the motion of damper assembly 300 at an end of stroke(e.g., extension, compression, etc.). As shown in FIG. 6C, end cap 332is a hard stop for an extension end of stroke for damper assembly 300.According to an exemplary embodiment, the extension forces from plunger312 and shaft 338 are imparted to end cap 332 through secondary plunger326. The secondary plunger 326 and the flow of fluid through the conduitreduces the magnitude of the extension forces and the total energyimparted on cap 332 by plunger 312 and shaft 338.

According to an exemplary embodiment, end cap 332 includes a contact end333 and has a cylindrical shape that defines an inner volume. Theopposing surface of secondary plunger 326 engages contact end 333 of endcap 332 to limit further movement of plunger 312 and shaft 338 alongdirection of travel 340. It should be understood that return spring 334compresses as plunger 312 and secondary plunger 326 travel toward endcap 332. According to an exemplary embodiment, return spring 334 has anouter diameter that is smaller than contact end 333 of end cap 332 suchthat return spring 334 extends within the inner volume of end cap 332.Return spring 334 nests within the inner volume of cap 332 as plunger312 and secondary plunger 326 translate toward end cap 332 alongdirection of travel 340.

According to an alternative embodiment, a vehicle suspension systemincludes an external hard stop that interfaces with another suspensioncomponent. By way of example, the suspension system may include apolymeric cushion coupled to a chassis of the vehicle that contacts aswing arm. Secondary plunger 326 in such a suspension system may notcontact end cap 332 (i.e., the end of stroke for the installed damperassembly 300 may occur before maximum extension). According to analternative embodiment, the suspension system includes an external hardstop (e.g., a polymeric cushion) and also a secondary plunger 326 thatengages end cap 332 to distribute the total stopping forces to varioussuspension components. According to still another alternativeembodiment, damper assembly 300 includes another type of internal hardstop (e.g., a snap ring positioned within and internal groove of housing314, a stud protruding into the inner volume of housing 314, etc.). Theinternal hard stop may engage plunger 312, secondary plunger 326, orstill another component of damper assembly 300.

Referring next to FIG. 6D, plunger 312 translates along direction oftravel 282 and away from secondary plunger 326. By way of example, suchmotion may occur after the vehicle has encountered a negative obstacleas the wheel end begins to travel upward thereby compressing damperassembly 300. According to an alternative embodiment, the motion ofplunger 312 away from secondary plunger 326 occurs after the vehicle hasencountered a positive obstacle and the wheel end begins to traveldownward thereby extending damper assembly 300 (e.g., where recoildamper 310 is incorporated to dissipate energy at a jounce end ofstroke). Translation of plunger 312 along direction of travel 282increases the pressure of the fluid within compression chamber 342 anddecreases the pressure of the fluid within recoil chamber 330 andextension chamber 318. Fluid flows into extension chamber 318 throughflow port 320 as plunger 312 translates along the direction of travel340, according to an exemplary embodiment.

As shown in FIG. 6D, the sidewall of housing 314 includes first portionhaving a first diameter and a second portion having a second diameter,the transition between the first diameter and the second diameterforming a shoulder, shown as step 344. According to an exemplaryembodiment, the length of the first portion defines the distance overwhich recoil damper 310 dissipates energy and provides a supplementaldamping force. As shown in FIG. 6D, secondary plunger 326 is coupled tothe first portion with interfacing member 328. As shown in FIG. 6D, thediameter of secondary plunger 326 is greater than the second diametersuch that the secondary plunger 326 translates only within the firstportion of housing 314. Step 344 thereby limits the motion of secondaryplunger 326 and prevents secondary plunger 326 from sliding (e.g., dueto gravity, due to locking forces between secondary plunger 326 andplunger 312, etc.) toward the second end 324 of housing 314. Accordingto an exemplary embodiment, plunger 312 has a diameter that isapproximately equal to the second diameter and is configured totranslate along both the first portion and the second portion of housing314. In some embodiments, plunger 312 is coupled to housing 314 with anintermediate seal.

According to an exemplary embodiment, return spring 334 includes a firstend coupled to end cap 332 and a second end coupled to secondary plunger326. As plunger 312 translates along direction of travel 282, returnspring 334 extends from a contracted position (e.g., nested within endcap 332) to an extended position. According to an exemplary embodiment,the contact surface of secondary plunger 326 engages step 344 whenreturn spring 334 is in the extended position. The extension of returnspring 334 repositions secondary plunger 326 such that recoil damper 310may again dissipate energy and provide a supplemental damping force(e.g., as the vehicle interacts with a subsequent positive or negativeobstacle). As return spring 334 extends, fluid is drawn from extensionchamber 318 into recoil chamber 330 such that fluid is again availableto flow through the conduit, dissipate energy, and provide asupplemental damping force. According to an alternative embodiment,recoil damper 310 does not include return spring 334 and secondaryplunger 326 travels downward toward step 344 due to another force (e.g.,coupling forces between plunger 312 and secondary plunger 326,gravitation forces, etc.).

As shown in FIG. 6D, translation of plunger 312 along the direction oftravel 340 from the position shown in FIG. 6C separates plunger 312 fromthe secondary plunger 326. According to an alternative embodiment,plunger 312 maintains engagement with the secondary plunger 326 untilthe secondary plunger 326 engages step 344. According to an exemplaryembodiment, damping groove 336 facilitates separation of plunger 312from the secondary plunger 326 as plunger 312 translates along directionof travel 340. Damping groove 336 reduces the risk that coupling forceswill lock plunger 312 to the secondary plunger 326 (e.g., due to contactbetween the two otherwise smooth corresponding surfaces). Such couplingforces may otherwise result in the translation of secondary plunger 326along the length of housing 314 while in contact with plunger 312, thecombination of secondary plunger 326 and plunger 312 providingsupplemental damping forces in unintended stroke positions (e.g., inlocations other than at an end of housing 314, etc.).

Referring now to FIGS. 7A-7C a suspension component, shown as a damperassembly 500, is shown according to an exemplary embodiment. The damperassembly 500 may be an integrated spring damper. The integrated springdamper may have a damping element that dissipates energy and a springelement that absorbs energy. Damper assembly 500 may be generallysimilar in structure to the damper assembly 300 discussed above. Likereference numerals are used in FIG. 7A to refer to features of thedamper assembly 500 that may be similar to or the same as those of thedamper assembly 300. In the example shown in FIG. 7A, a side wall of thehousing 314 is removed for purposes of illustration. However, it shouldbe understood that the housing 314 still includes such a side wall,which defines an internal volume.

As shown in FIG. 7A, a shaft 338 may translate within an internal volumedefined by the inner surface of the housing 314 (shown in FIG. 6D). Theshaft 338 may translate between an extended position and a retractedposition. In an exemplary embodiment, a piston, shown as a plunger 312,is coupled to the shaft 338 such that the plunger 312 moves within thehousing 314 (shown in FIG. 6D) in a manner that corresponds to thetranslation of the shaft 338. A limiter, shown as a recoil damper 510,may also be disposed within the housing 314 (shown in FIG. 6D), betweenthe plunger 312 and end cap 332. In an exemplary embodiment, the recoildamper 510 is similar to the recoil damper 310.

Recoil damper 510 includes a piston, shown as secondary plunger 526. Asshown in FIG. 7A, secondary plunger 526, is an annular member positionedwithin an extension chamber. Secondary plunger 526 includes a contactsurface 527 that is configured to engage plunger 312. An opposingsurface 529 of secondary plunger 526 is separated from the contactsurface 527 by the thickness of secondary plunger 526. According to anexemplary embodiment, secondary plunger 526 is coupled to an innersidewall of housing 314 (shown in FIG. 6D) with a seal (e.g., ring, wearband, guide ring, wear ring, etc.). In various embodiments, an outersurface of the secondary plunger 526 includes a groove 531 that extendsthroughout the entire circumference of the secondary plunger 526. Thegroove 531 is configured to receive a seal that couples the secondaryplunger 526 to the side wall of the housing 314 (shown in FIG. 6D). Inan exemplary embodiment, the seal is similar to the interfacing member328.

According to an exemplary embodiment, recoil damper 510 includes aresilient member, shown as return spring 334. As shown in FIG. 7A,return spring 334 extends between a first end that engages secondaryplunger 526 and a second end that engages end cap 332. Return spring 334may be an interlaced wave spring (i.e., a flat wire compression spring),a coil spring, or another type of spring. Return spring 334 positionssecondary plunger 526 within housing 314 (shown in FIG. 6D). The springforce generated by return spring 334 may overcome gravity (e.g., wheredamper assembly 500 is positioned in a vehicle suspension system withsecondary plunger 526 above end cap 332) or may position secondaryplunger 526 more quickly than gravity alone (e.g., where damper assembly500 is positioned in a vehicle suspension system with secondary plunger526 below end cap 332, as shown in FIG. 5). Return spring 334 is notintended to damp the movement of plunger 312, and return spring 334 mayhave a relatively small spring constant (e.g., less than 500 pounds perinch). According to an alternative embodiment, recoil damper 510 doesnot include a return spring 334. Such a recoil damper may repositionsecondary plunger 526 using gravity or an alternative device.

As shown in FIG. 7B, secondary plunger 526 defines a plurality ofchannels (i.e., track, depression, kerf, notch, opening, recess, slit,etc.) through which hydraulic fluid may flow between different chamberscreated by the secondary plunger 526 (i.e., a first chamber between theprimary plunger 312 and the secondary plunger 526 and a second chamberbetween the secondary plunger 526 and the end 324 of the housing 314).In the exemplary embodiment shown, each channel includes an oppositesurface groove 512 disposed on the opposite surface 529, an inner groove516 disposed on an inner cylindrical face 533 of the secondary plunger526, and a contact groove 514 disposed on the contact surface 527 of theplunger. In the example shown, each of the opposite surface groove 512and the contact groove 514 extend across portions of the surfaces 508and 511. In an exemplary embodiment, the grooves 512-516 aresubstantially similar in shape. The grooves 512-516 may be arcuate andhave a constant radius of curvature. In an alternative embodiment, theopposite surface groove 512 and the inner groove 516 are similarlyshaped, while the contact groove 514 is differently shaped. In oneembodiment, the opposite surface groove 512 and the inner groove 516 arecurved, while the contact groove 514 is substantially rectangular andnarrower than the opposite surface groove 512 and the contact groove516. In some embodiments, the contact surface 527 of the secondaryplunger 526 engages with an upper surface of the plunger 312 when thedamper assembly 500 is in a contracted position, and the contact groove514 interfaces with the upper surface to form a conduit for hydraulicfluid to flow to a chamber above the secondary plunger 526.

As the plunger 312 traverses towards or away from the first end 322 andchanges the volumes of the chambers created by the secondary plunger526, hydraulic fluid flows through the channels created by the grooves512-516. By way of example, the plunger 312 may move away from the firstend 322 (e.g., as a result of the vehicle encountering a positiveobstacle), and the pressure of the fluid in the chamber between thesecondary plunger 526 and the end 322 may decrease. Fluid flow from thischamber may occur through the channel defined by the grooves 512-514towards the primary plunger 312. The grooves 512-516 may be configuredto restrict fluid flow to provide an additional damping forceproportional to the pressure difference between the fluids in each ofthe chambers. Thus, through such a configuration, the secondary plunger526 provides an additional damping force when the pressure differencesare greatest (e.g., when the damper assembly 500 is at the end of astroke).

As shown in FIG. 7C, the opposite surface grooves 512 are spaced aroundthe circumference of the secondary plunger 526 (e.g., equally,symmetrically, unequally, etc.). As shown in FIG. 7C, each of theopposite surface grooves 512 extends along the opposing surface 529 atan angle relative a radial reference line passing through its center(e.g., each of the opposite surface grooves 512 is non-radial). By wayof example, FIG. 7C shows a radial reference line 513 that extends fromthe axis 515 of the secondary plunger 526 through a center 517 of one ofthe opposite surface grooves 512.

As shown in FIG. 7C, pairs of the opposite surface grooves 512 define achord of the circle defined by the outer cylindrical face of thesecondary plunger 526. The opposite surface grooves 512 in each pair arealigned along the chord and positioned substantially parallel to oneanother, according to one embodiment. Because the contact grooves 514and the inner grooves 516 defining the channels are substantiallyaligned with the opposite surface grooves 512, such an arrangementfacilitates a uniform distribution of flow between the chambers. Thedistribution of opposite surface grooves 512 is an improvement over onlyproviding a single channel, which may result in lateral forces,rotational forces, and/or wear on the secondary plunger 526, the shaft338, and/or the plunger 312.

As shown in FIG. 7A, plunger 312 defines a contact surface that isconfigured to engage the contact surface 527 of secondary plunger 526.According to an exemplary embodiment, the contact surface of plunger 312and the contact surface 527 of secondary plunger 526 are complementary(i.e., corresponding, matched, correlative, etc.) thereby reducing therisk of pressurized fluid seeping across the contact surfaces of plunger312 and secondary plunger 526. According to an alternative embodiment, aseal is positioned between plunger 312 and secondary plunger 526.

According to an alternative embodiment, plunger 312 defines a channel.The channel of plunger 312 may correspond to the contact groove 514 ofthe secondary plunger 526 such that the channel of plunger 312 and thecontact groove 514 of secondary plunger 526 together form a flowconduit. In other embodiments, the channel of plunger 312 does notcorrespond to the contact groove 514 of secondary plunger 526 such thata plurality of flow conduits are formed between the contact groove 514and the contact surface of plunger 312.

According to an exemplary embodiment, the grooves 512-516 are shaped todissipate a target amount of energy and/or provide a target supplementaldamping force (e.g., due to fluid flow through the conduit). Accordingto an exemplary embodiment, fluid flow does not occur between secondaryplunger 526 and the sidewall of housing 314. Secondary plunger 526(e.g., with a seal disposed in the groove 531) may limit fluid flow to aflow path through the channels defined by grooves 512-516. Recoil damper510 thereby generates fluid flow paths through the channels, andperformance characteristics may be tuned as a function only of thefeatures of the grooves 512-516, according to an exemplary embodiment.Limiting fluid from flowing between secondary plunger 526 and an innersidewall of housing 314 also provides more predictable and uniformenergy dissipation and supplemental damping forces (i.e., additionalflow paths may introduce additional variability into the energydissipated by a limiter).

Referring now to FIG. 8, a top view of an alternative secondary plunger626 is shown, according to an exemplary embodiment. The secondaryplunger 626 may be used in place of the secondary plunger 326 and/or thesecondary plunger 526. The secondary plunger 626 may share features withthe secondary plunger 526 (e.g., grooves on an inner cylindrical face612 thereof and grooves on a contact surface thereof).

In the example shown, an opposing surface 610 (i.e., a surface of thesecondary plunger 626 that is further away from the plunger 312)includes a first groove 602, a second groove 604, a third groove 606,and a fourth groove 608. As shown in FIG. 8, each of the first groove602, second groove 604, third groove 606, and fourth groove 608 extendalong an opposing surface 610 at an angle relative a radial referenceline passing through its center (e.g., each of the first groove 602,second groove 604, third groove 606, and fourth groove 608 arenon-radial). By way of example, FIG. 8 shows a first angle 601 formedbetween a first radial reference line 603 that extends from the axis 615of the secondary plunger 626 and passes through a center 605 of thefirst groove 602. Similarly, FIG. 8 shows a second angle 607 formedbetween a second radial reference line 609 that extends from the axis615 of the secondary plunger 626 and passes through a center 611 of thesecond groove 604. In the embodiment shown in FIG. 8, the first angle601 and the second angle 607 are the same. Alternatively they may bedifferent.

As shown in FIG. 8, first ends of the first groove 602 and the thirdgroove 606 are substantially aligned at a first diameter of the circledefined by the inner cylindrical face 612. Additionally, the firstgroove 602 and the third groove 606 extend away from the first ends,across the entirety of the opposing surface 610, and substantiallyparallel to one another. Second ends of the grooves 602 and 606 (e.g.,ends closer to an outer surface 614 of the secondary plunger 626) areoffset from one another. Grooves 602 and 606 may be substantiallyparallel to one another but on opposing sides of the secondary plunger626 such that fluid flowing through channels created by the grooves 602and 606 provides counterbalancing forces on the secondary plunger 626.Rotation of the secondary plunger 626, and resulting wear and tear onany components (e.g., a shaft or return spring) may be reduced (e.g.,eliminated, etc.).

First ends of the second groove 604 and the fourth groove 608 aresubstantially aligned at a second diameter of the circle defined by theinner cylindrical face 612. In one embodiment, the first diameter (thediameter at which first ends of the first and third grooves 602 and 606are aligned) is perpendicular to the second diameter. The second groove604 and the fourth groove 608 extend away from the first ends, acrossthe entirety of the opposing surface 610, and substantially parallel toone another. Second ends of the grooves 604 and 608 (e.g., ends closerto an outer surface 614 of the secondary plunger 626) are offset fromone another. In one embodiment, the first and third grooves 602 and 606extend in a direction that is substantially perpendicular to thedirection that the second and fourth grooves 604 and 608 extend. Thesecond groove 604 and the fourth groove 608 may be substantiallyparallel to one another but on opposing sides of the secondary plunger626 such that fluid flowing through channels created by the grooves 604and 608 provides counterbalancing forces on the secondary plunger 626.Rotation of the secondary plunger 626, and resulting wear and tear onany components (e.g., a shaft or return spring) may be reduced (e.g.,eliminated, etc.).

As shown in FIG. 8, around the circumference of the secondary plunger626, there are grooves of alternating orientations. The grooves may besubstantially perpendicular to one another. Such grooves furtherfacilitate the counterbalancing of directional forces placed on thesecondary plunger 626 by fluid flow. In an exemplary embodiment, thesecondary plunger 626 also includes grooves on a contact surface thereof(e.g., a surface opposite to the opposing surface 610). The grooves maybe similar to the grooves 514 and may establish a fluid conduit with theplunger 312. In one such embodiment, the grooves on the contact surfaceare directly below each of the grooves 602-608 and substantiallyparallel to the grooves 602-608.

Returning now to FIG. 4, the recoil damper 236 of the integrated springdamper 200 includes a recoil piston 238 positioned within the secondchamber 228 and a resilient member such as an interlaced wave spring(i.e., a flat wire compression spring), a coil spring, or another typeof spring. The resilient member may be disposed between the recoilpiston 238 and the barrier 206. According to an exemplary embodiment,the resilient member is not intended to damp the movement of the mainpiston 224 but positions the recoil piston 238 within the main body 202,such as after it has been displaced by the main piston 224. In otherembodiments, the recoil damper 236 may not include a resilient memberand the recoil piston 238 may be repositioned using gravity or analternative device.

Occupants within a vehicle experience large impulse forces as the mainpiston 224 contacts the barrier 206 or a component of the suspensionsystem engages a hard stop. The recoil damper 236 reduces such impulseforces transmitted to occupants within the vehicle by dissipating aportion of the kinetic energy of the main piston 224 and the main tube216 (i.e., provide a supplemental damping force) as the integratedspring damper assembly 200 reaches an end of stroke (e.g., as the pistonreaches a recoil end of stroke, as the piston reaches a jounce end ofstroke, etc.).

The first chamber 226, the second chamber 228, and the first innerchamber 232 contain a generally non-compressible fluid (e.g., hydraulicfluid, oil, etc.). The first inner chamber 232 is in fluid communicationwith the first chamber 226 through an opening 225 in the main piston224. The fluid may flow between the first chamber 226 and the secondchamber 228 through a passage 242 (e.g., conduit, bore, etc.) in abypass manifold 240. According to an exemplary embodiment, the bypassmanifold 240 is a structure coupled to the side of the main body 202.The passage 242 is in fluid communication with the first chamber 226through an aperture 244 in the main body 202 and with the second chamber228 through an aperture 246 in the main body 202. According to anexemplary embodiment, the aperture 246 opens into the second chamber 228between the main piston 224 and the recoil piston 238. The flow of fluidthrough the passage 242 is controlled by a flow control device 248.According to an exemplary embodiment, the flow control device 248 is adisk valve disposed within the bypass manifold 240 along the passage242. In other embodiments, the flow control device 248 may be anotherdevice, such as a pop off valve, or an orifice. In other embodiments,the flow control device remotely positioned but in fluid communicationwith the first chamber 226 and the second chamber 228.

The second inner chamber 234 contains a generally compressible fluidthat may include (e.g., at least 90%, at least 95%) an inert gas such asnitrogen, argon, or helium, among others. In some embodiments, thesecond inner chamber 234 is in fluid communication with externaldevices, such as one or more reservoirs (e.g., central reservoir, tank),an accumulator, or device allowing the pressure of the gas to beadjusted. The pressure of the gas may be adjusted by removing or addinga volume of gas to adjust the suspension ride height.

When the integrated spring damper assembly 200 is compressed orextended, the main tube 216 translates relative to the main body 202.The gas held in the second inner chamber 234 compresses or expands inresponse to relative movement between the main tube 216 and the dividingpiston 230, which may remain relatively stationary but transmit pressurevariations between the incompressible hydraulic fluid in the first innerchamber 232 and the compressible fluid in second inner chamber 234. Thegas in the second inner chamber 234 resists compression, providing aforce that is a function of the compressibility of the gas, the area ofthe piston, the volume and geometry of the chamber, and the currentstate (e.g., initial pressure) of the gas, among other factors. Thereceipt of potential energy as the gas is compressed, storage ofpotential energy, and release of potential energy as the gas expandsprovide a spring function for the integrated spring damper assembly 200.

Movement of the main tube 216 relative to the main body 202 translatesthe main piston 224, causing the volume of the first chamber 226 and thesecond chamber 228 to vary. When the integrated spring damper assembly200 compresses, the volume of the first chamber 226 decreases while thevolume of the second chamber 228 increases. The fluid is forced from thefirst chamber 226 through the passage 242 and past the flow controldevice 248 into the second chamber 228. The resistance to the flow ofthe fluid through the passage 242 provides a damping function for theintegrated spring damper assembly 200 that is independent of the springfunction.

Referring to FIGS. 9A-9F, an integrated spring damper 800 is shown,according to another exemplary embodiment. As shown in FIG. 9A, theintegrated spring damper 800 includes a tubular element (e.g.,cylindrical, etc.), shown as main body 802. In one embodiment, the mainbody 802 is manufactured using an extrusion process. In an alternativeembodiment, the main body 802 is manufactured using a casting process.As shown in FIGS. 9A and 9C, a cap, shown as cap 804, and a barrier,shown as barrier 806, are disposed on opposing ends of the main body802, defining an internal volume. The integrated spring damper 800further includes a tubular element (e.g., cylindrical, etc.), shown asmain tube 816. The main tube 816 is at least partially received withinthe internal volume of the main body 802. The main tube 816 isconfigured to translate with respect to the main body 802. As shown inFIG. 9C, a cap, shown as cap 818, is disposed at a distal end of themain tube 816. The cap 804, barrier 806, and cap 818 may be coupled tothe respective components with a threaded connection or with anothercoupling mechanism (e.g., welding, a friction weld, brazing,interference fit, etc.). As shown in FIG. 9A, in some embodiments, theintegrated spring damper 800 includes a locking mechanism, shown aslocking mechanism 870. In one embodiment, the locking mechanism 870 isconfigured to position (e.g., lock, index, etc.) the cap 804 in a targetorientation relative to the main body 802. In one embodiment, thelocking mechanism 870 includes a set screw that is tightened tofacilitate locking the cap 804 in the target orientation. The lockingmechanism 870 may facilitate indexing a lower mount of the integratedspring damper 800 relative to other components thereof and therebyfacilitate mounting integrated spring damper 800 onto a vehicle.

According to an exemplary embodiment, the integrated spring damper 800includes a first mounting portion (e.g., a lower mounting portion,etc.), shown as eyelet 820, with which the integrated spring damper 800is coupled to one portion of an axle assembly (e.g., a lower portion ofthe axle assembly, etc.). According to an exemplary embodiment, theintegrated spring damper 800 is coupled on one end (e.g., with theeyelet 820 on a lower end, etc.) to a moveable member of the axleassembly (e.g., a lower support arm, etc.). According to an exemplaryembodiment, the eyelet 820 is integrally formed with the cap 804. Asshown in FIG. 9A, the integrated spring damper 800 includes a secondmounting portion (e.g., an upper mounting portion, a pin mount, etc.),shown as upper mount 807. The upper mount 807 is configured to couple anopposing second end (e.g., an upper end, etc.) of the integrated springdamper 800 to a vehicle structural element, vehicle body, frame member,or part thereof (e.g., chassis, side plate, hull, etc.), shown as sideplate 1000.

According to an exemplary embodiment, the eyelet 820 includes a firstear 902 and a second ear 904. In the embodiment shown, the first ear 902includes a first opening 903 (also see FIG. 10A) and the second ear 904includes a second opening 905 (also see FIG. 10A). The first and secondopenings are circular and of the same diameter. It should be understoodthat, in various alternative embodiments, the openings may be shapeddifferently or differently from one another. In the embodiment shown,the openings in the first and second ears 902 and 904 are aligned withone another to facilitate the insertion of a mounting pin 906therethrough.

In the embodiment shown, the mounting pin 906 is substantiallycylindrical in shape. In one embodiment, the length of the mounting pin906 is greater than a distance between outer surfaces of the first andsecond ears 902 and 904. With the mounting pin 906 inserted andcentered, a first end 908 of the mounting pin 906 extends outwardly fromthe first ear 902. Additionally, a second end of the mounting pin 906extends outwardly from the second ear 904. As described below withrespect to FIGS. 10A-10I, in addition to being inserted into the ears902 and 904 of the eyelet 820, the mounting pin 906 is also insertedthrough an element (e.g., a swing arm, etc.) that is coupled to an axleassembly of a vehicle to rotatably couple the integrated spring damper800 to the axle assembly. In some embodiments, the mounting pin 906includes an opening that extends from the first end to the second end.

As shown in FIGS. 9A and 9C-9D, the upper mount 807 includes a firstmounting member 808, a second mounting member 810, a third mountingmember 812, and a fourth mounting member 814. As shown in FIGS. 9A and9D, the first mounting member 808 is disposed proximal the cap 818 andpositioned such that an upper surface of the first mounting member 808abuts a first surface of the side plate 1000, shown as bottom surface1002. In one embodiment, the first mounting member 808 is constructedfrom a metal or wear resistant material. As shown in FIG. 9C-9D, thesecond mounting member 810 includes a portion (e.g., a lower portion, afirst portion, a non-protruded portion, etc.) that is positionedproximal both the first mounting member 808 and the cap 818.Specifically, the second mounting member 810 is positioned between thecap 818 and the first mounting member 808. In one embodiment, the secondmounting member 810 is a resilient member, such as a flexible urethane,that serves as an isolator and an elastomeric spacer. The secondmounting member 810 may be configured to isolate the cap 818 from atleast one of the first mounting member 808 and the side plate 1000. Insome embodiments, the first mounting member 808 and the second mountingmember 810 are annular and circular in shape. In other embodiments, thefirst mounting member 808 and the second mounting member 810 haveanother shape (e.g., discus square, hexagonal, etc.).

In some embodiments, the first mounting member 808 is friction welded tothe second mounting member 810. For example, planar portions of thesurface of the first mounting member 808 that are to be disposed nearestthe cap 818 may be forced against planar portions of the surface of thesecond mounting member 810 that is to be disposed nearest a side plate1000. Rotational energy may be applied to at least one of the firstmounting member 808 and the second mounting member 810 while themounting members 808 and 810 are pressed against one another untilfriction welds 890 and 892 join the mounting members 808 and 810together. In one embodiment, the first and second mounting members 808and 810 are substantially circular and define apertures 809 and 811through which a protruding portion 819 of the cap 818 extends. Thefriction welds 890 and 892 may circumferentially surround the aperture809.

As shown in FIGS. 9A and 9D, the fourth mounting member 814 ispositioned between the side plate 1000 and the third mounting member812. A second surface, shown as top surface 1004, of the side plate 1000is in contact with a bottom surface of the fourth mounting member 814,and the third mounting member 812 is disposed on a top surface of thefourth mounting member 814. The first mounting member 808 and the fourthmounting member 814 are spaced to receive the side plate 1000. In oneembodiment, the fourth mounting member 814 is a resilient member, suchas a flexible urethane, that serves as an isolator and an elastomericspacer. The fourth mounting member 814 may be configured to isolate thethird mounting member 812 from the side plate 1000. In one embodiment,the third mounting member 812 is constructed from a metal or wearresistant material. In some embodiments, the third mounting member 812and the fourth mounting member 814 are annular and circular in shape. Inother embodiments, the third mounting member 812 and the fourth mountingmember 814 have another shape (e.g., discus square, hexagonal, etc.).

In some embodiments, the fourth mounting member 814 is friction weldedto the third mounting member 812. For example, planar portions of asurface of the third mounting member 812 may be forced against planarportions of a surface of the fourth mounting member 814. Rotationalenergy may be applied to at least one of the third mounting member 812and the fourth mounting member 814 while the mounting members 812 and814 are pressed against one another until friction welds 894 and 896join the mounting members 812 and 814 together. In one embodiment, thethird and fourth mounting members 812 and 814 are substantially circularand define apertures 813 and 817 through which a protruding portion 819of the cap 818 extends. The friction welds 894 and 896 maycircumferentially surround the apertures 813 and 817.

As shown in FIG. 9D, the first mounting member 808 defines an aperture,shown as first member aperture 809, that corresponds with (e.g., alignswith, cooperates with, etc.) an aperture defined by side plate 1000,shown as locating aperture 1006. The second mounting member 810 includesa protruded portion (e.g., a second portion, an upper portion, etc.)that extends through the first aperture 809 and the locating aperture1006 and is engaged with a recess, shown as recess 815, defined by thefourth mounting member 814. In one embodiment, the recess 815 receivesthe protruded portion of the second mounting member 810. The secondmounting member 810 defines an aperture, shown as second member aperture811, that extends longitudinally through the second mounting member 810and aligns with (e.g., cooperates with, etc.) an aperture, shown asthird member aperture 813, and an aperture, shown as fourth memberaperture 817, defined by the third mounting member 812 and the fourthmounting member 814, respectively. The second member aperture 811, thirdmember aperture 813, and fourth member aperture 817 receive a capprotrusion 819 (e.g., a protruded portion 819 of the cap 818).

As shown in FIG. 9C, a main piston, shown as main piston 824, isdisposed in the internal volume of the main body 802. The main piston824 is coupled to the main tube 816 and slidably engages the main body802. The main piston 824 separates the internal volume into a firstchamber 826 (e.g., compression chamber, etc.) and a second chamber 828(e.g., extension chamber, etc.). The first chamber 826 is a generallycylindrical chamber that includes the portion of the internal volume ofthe main body 802 between the main piston 824 and the cap 804. Thesecond chamber 828 is an annular chamber defined between the main body802 and the main tube 816 and extends between the main piston 824 andthe barrier 806. When the main tube 816 translates relative to the mainbody 802, the main piston 824 changes the volume of the first chamber826 and the second chamber 828. A dividing piston, shown as dividingpiston 830 (e.g., floating piston, etc.), is disposed in the main tube816 and slidably engages the main tube 816. The dividing piston 830separates the internal volume of the main tube 816 into a first innerchamber 832 and a second inner chamber 834. According to an exemplaryembodiment, the first inner chamber 832 is open to (i.e., in fluidcommunication with, etc.) the first chamber 826.

According to an exemplary embodiment, the first chamber 826, the secondchamber 828, and the first inner chamber 832 contain a generallynon-compressible fluid (e.g., hydraulic fluid, oil, etc.). According toan exemplary embodiment, the second inner chamber 834 contains agenerally compressible fluid that may include (e.g., at least 90%, atleast 95%) an inert gas such as nitrogen, argon, or helium, amongothers. In some embodiments, the second inner chamber 834 is in fluidcommunication with external devices, such as one or more reservoirs(e.g., central reservoir, tank, etc.), an accumulator, or a deviceallowing the pressure of the gas to be adjusted with a pressureregulation line. The pressure of the gas may be adjusted by removing oradding a volume of gas to adjust the suspension ride height.

According to an exemplary embodiment, the integrated spring damper 800includes a pressure regulation line that is located at a top portion(e.g., a top end, an upper end, etc.) of the integrated spring damper800. As shown in FIGS. 9A-9D, the integrated spring damper 800 includesa port, shown as pressure regulation port 880, coupled to the protrudedportion 819 of the cap 818 (e.g., with a threaded interface, welded,etc.). As shown in FIGS. 9C-9D, the pressure regulation port 880 definesa passageway, shown as inlet passageway 882. The protruded portion 819of the cap 818 defines a passageway, shown as intermediate passageway822. The intermediate passageway 822 cooperates with the inletpassageway 882 to define the pressure regulation line of the integratedspring damper 800. The pressure regulation line extends from thepressure regulation port 880, through the protruded portion 819 of thecap 818, and into the second inner chamber 834 of the main tube 816 suchthat it is fluidly connected to the second inner chamber 834. Accordingto an exemplary embodiment, the pressure regulation line of theintegrated spring damper 800 facilitates increasing or decreasing avolume of fluid (e.g., an inert gas, etc.) within the second innerchamber 834 of the main tube 816.

According to an exemplary embodiment, the pressure regulation port 880is positioned at the top of the integrated spring damper 800 to providea fixed or static location to fill or release gas from the second innerchamber 834 of the integrated spring damper 800. The pressure regulationport 880 is positioned to increase (e.g., maximize, etc.) the travel ofthe main tube 816 within the main body 802, thereby increasing thestroke of the integrated spring damper 800. By way of example, impulseforces transmitted to occupants within a vehicle from bumps, pot holes,etc. may be reduced by increasing the maximum stroke of the integratedspring damper 800. According to an exemplary embodiment, the pressureregulation port 880 is positioned above the side plate 1000 to reducethe risk of debris (e.g., dirt, rocks, mud, etc.) damaging or blockingthe pressure regulation port 880.

When the integrated spring damper 800 is compressed or extended, themain tube 816 translates relative to the main body 802. The gas held inthe second inner chamber 834 compresses or expands in response torelative movement between the main tube 816 and the dividing piston 830,which may remain relatively stationary but transmit pressure variationsbetween the incompressible hydraulic fluid in the first inner chamber832 and the compressible fluid in second inner chamber 834. The gas inthe second inner chamber 834 resists compression, providing a force thatis a function of the compressibility of the gas, the area of the piston,the volume and geometry of the second inner chamber 834, and the currentstate (e.g., initial pressure, etc.) of the gas, among other factors.The receipt of potential energy as the gas is compressed, storage ofpotential energy, and release of potential energy as the gas expandsprovide a spring function for the integrated spring damper 800.

In one embodiment, a recessed area is disposed in the dividing piston830. In FIG. 9C the recessed area is shown as cup 831. According to theexemplary embodiment shown in FIG. 9C, the dividing piston 830 ispositioned such that the cup 831 facilitates an increase in the volumeof the second inner chamber 834. In other embodiments, the dividingpiston 830 is positioned such that the cup 831 facilitates an increasein the volume of the first inner chamber 832. The dividing piston 830may be flipped and repositioned to selectively increase the volume ofthe first inner chamber 832 or the second inner chamber 834 to tune theperformance of the integrated spring damper 800. As shown in FIG. 9C,the cap 818 defines a pocket, shown as cap pocket 823. The cap pocket823 is structured to increase the volume of the second inner chamber834. In some embodiments, the cap pocket 823 and the cup 831 increasethe volume of the second inner chamber 834. In other embodiments, atleast one of the cap pocket 823 and the cup 831 are not defined by thecap 818 and the dividing piston 830, respectively. By way of example,increasing the volume of the second inner chamber 834 (i.e., decreasingthe gas pressure within the second inner chamber 834, etc.) mayfacilitate a softer ride (e.g., a smaller spring force, etc.), whiledecreasing the volume of the second inner chamber 834 (i.e., increasingthe gas pressure within the second inner chamber 834, etc.) mayfacilitate a stiffer ride (e.g., a greater spring force, etc.).

Referring again to FIG. 9C, a limiter, shown as recoil damper 836, isdisposed within the internal volume of the main body 802, between themain piston 824 and the barrier 806. The recoil damper 836 reduces therisk of damage to the main piston 824, barrier 806, the sidewall of mainbody 802, and still other components of integrated spring damper 800 byreducing the forces imparted by the main piston 824 as it travels towardan end of stroke (i.e., the maximum travel of the stroke, etc.).According to an exemplary embodiment, the recoil damper 836 includes arecoil piston, shown as recoil piston 838, positioned within the secondchamber 828 and a resilient member, shown as resilient member 839. Theresilient member 839 may include an interlaced wave spring (i.e., a flatwire compression spring, etc.), a coil spring, or another type ofspring. The resilient member 839 may be disposed between the recoilpiston 838 and the barrier 806. According to an exemplary embodiment,the resilient member 839 is not intended to substantially resist themovement of the main piston 824 but positions the recoil piston 838within the main body 802, such as after it has been displaced by themain piston 824. In other embodiments, the recoil damper 836 does notinclude a resilient member, and the recoil piston 838 may berepositioned using gravity or an alternative device.

Occupants within a vehicle experience large impulse forces as the mainpiston 824 contacts the barrier 806 or a component of the suspensionsystem engages a hard stop. The recoil damper 836 reduces such impulseforces transmitted to occupants within the vehicle by dissipating aportion of the kinetic energy of the main piston 824 and the main tube816 (i.e., provide a supplemental damping force, etc.) as the integratedspring damper 800 reaches an end of stroke (e.g., as the piston reachesa recoil end of stroke, as the piston reaches a jounce end of stroke,etc.).

Referring now to FIGS. 9E-9F, the first chamber 826 and the secondchamber 828 are fluidly connected (e.g., such that fluid may flowbetween them) through at least one of a first passage 852 (e.g.,conduit, bore, etc.) of a flow path, shown as first flow path 850,defined by a manifold, shown as bypass manifold 840, and a secondpassage 862 of a flow path, shown as second flow path 860, also definedby bypass manifold 840. In other embodiments, the bypass manifold 840defines a different number of passages (e.g., one, three, etc.).According to an exemplary embodiment, the bypass manifold 840 is coupledto the side of the main body 802 (e.g., removably coupled to the mainbody 802 with a plurality of fasteners, etc.). In other embodiments, thebypass manifold 840 and the main body 802 are integrally formed (e.g., aunitary structure, etc.). According to an alternative embodiment, atleast one of the first passage 852 and the second passage 862 are formedwith tubular members coupled to an outer portion of the main body 802 orwith flow passages defined by the main body 802.

According to the exemplary embodiment shown in FIGS. 9C and 9E-9F,damping forces are generated as the flow of fluid through the firstpassage 852 and the second passage 862 interacts with flow controlelements, shown as first flow control device 858 and second flow controldevice 868. According to an exemplary embodiment, the first flow controldevice 858 and the second flow control device 868 are bidirectional flowvalves disposed within the bypass manifold 840 along the first passage852 and the second passage 862, respectively. The first flow controldevice 858 and the second flow control device 868 may include washersthat differentially restrict a fluid flow based on the direction thatthe fluid is flowing. In other embodiments, the first flow controldevice 858 and the second flow control device 868 are other types offlow control device, such as pop off valves or orifices (e.g., variableflow orifices, etc.). In other embodiments, the first flow controldevice 858 and the second flow control device 868 are remotelypositioned but in fluid communication with the first chamber 826 and thesecond chamber 828.

According to an exemplary embodiment, the main body 802 defines aplurality of sets of openings. As shown in FIG. 9E, the plurality ofsets of openings include a first set having openings 854 and openings856. The openings 854 and the openings 856 are fluidly coupled by thefirst passage 852. As shown in FIG. 9F, the plurality of sets ofopenings include a second set having openings 864 and openings 866. Theopenings 864 and the openings 866 are fluidly coupled by the secondpassage 862. According to an exemplary embodiment, the first passage 852and the second passage 862 are offset relative to one another bothcircumferentially and longitudinally along the length of the main body802 and the bypass manifold 840. In other embodiments, the main body 802defines a different number of sets of openings (e.g., one, three, four,etc.), each set corresponding with one of the passages defined by thebypass manifold 840.

According to an exemplary embodiment, the integrated spring damper 800provides different damping forces in extension and retraction and alsodamping forces that vary based on the position of the main piston 824relative to the main body 802 (e.g., position dependent dampening,etc.). According to an exemplary embodiment, the integrated springdamper 800 provides recoil damping forces in jounce and compressiondamping forces in recoil as part of a spring force compensationstrategy. By way of example, the position dependent dampening of theintegrated spring damper 800 may function as follows. As the main piston824 translates within main body 802 (e.g., due to relative movementbetween components of a vehicle suspension system, etc.), variousopenings and their corresponding passages are activated and deactivated.According to an exemplary embodiment, fluid flows through the activatedopenings and their corresponding passages to provide damping forces thatvary based on position and direction of travel of the main piston 824within the main body 802.

Movement of the main tube 816 relative to the main body 802 translatesthe main piston 824, causing the volume of the first chamber 826 and thesecond chamber 828 to vary. When the integrated spring damper 800compresses, the volume of the first chamber 826 decreases while thevolume of the second chamber 828 increases. The fluid is forced from thefirst chamber 826 through at least one of the openings 854 of the firstpassage 852 and the openings 864 of the second passage 862 (e.g., basedon the position of the main piston 824 within the main body 802, etc.).The fluid flows through at least one the first passage 852 and thesecond passage 862 past the first flow control device 858 and the secondflow control device 868 and out of the openings 856 and the openings 866into the second chamber 828. The resistance to the flow of the fluidalong at least one of the first passage 852 and the second passage 862and the interaction thereof with the first flow control device 858 andthe second flow control device 868 provides a damping function for theintegrated spring damper 800 that is independent of the spring function.By way of example, if the non-compressible fluid is able to flow throughboth the first passage 852 and the second passage 862, the dampeningprovided by the integrated spring damper 800 will be less than if fluidis able to flow through only one of the first passage 852 and the secondpassage 862. Therefore, as the main piston 824 moves towards the cap804, the integrated spring damper 800 provides a first dampeningcharacteristic (e.g., less dampening, etc.) when the openings 854 andthe openings 864 are active and a second dampening characteristics(e.g., more dampening, etc.) when only the openings 864 are active(e.g., because the main piston 824 deactivates the openings 854, whichmay include the openings 854 being positioned within the second chamber828, etc.).

Referring now to FIGS. 10A-10I, an integrated spring damper, shown asthe integrated spring damper 800, may be rotatably connected to amovable member, shown as a lower support arm 920, of an axle assembly ofa vehicle.

As shown in FIGS. 10A and 10B, the integrated spring damper 800 includesa main body, shown as the main body 802, a bypass manifold, shown as thebypass manifold 840, and an eyelet, shown as the eyelet 820. The eyelet820 includes a first ear 902 and a second ear 904, with each of the ears902 and 904 including openings structured to receive a coupling device,shown as a mounting pin 906. In the example shown, the mounting pin 906is substantially-cylindrical in shape.

The ears 902 and 904 of the eyelet 820 may be spaced apart such that thedistance between surfaces thereof is approximately equal to the width ofa mounting portion 922 of the lower support arm 920. The mountingportion 922 is substantially-cylindrical in shape and may be integratedwith the lower support arm 920 or separately attached to the lowersupport arm 920. The mounting portion 922 includes asubstantially-cylindrical passage 924. The mounting portion 922 isconfigured to receive the mounting pin 906 through the passage 924.

In one embodiment, the mounting pin rotatably couples the integratedspring damper 800 to the lower support arm 920, combinations of thrustwashers 914 and seals 912 are inserted into ends of the mounting portion922. In one embodiment, the seals 912 are annular and include an innerdiameter that is approximately equal to the diameter of the mounting pin906. The ears 902 and 904 may then be aligned with the passage 924 ofthe mounting portion 922. The mounting pin 906 may then be insertedthrough one of the openings in one of the ears 902 and 904, through acombination of a thrust washer 914 and a seal 912, through the passage924 of the mounting portion 922, through a combination of another thrustwasher 914 and another seal 912, and finally through the other one ofthe openings in one of the ears 902 and 904. In the embodiment shown inFIGS. 10A-10C, the seal 912 and thrust washer 914 from one end of thepassage are removed to simplify illustration (refer to FIGS. 10D-10F,which include the seals 912 and thrust washers 914 on both ends). In oneembodiment, fasteners 916 are inserted between the seals 912 and themounting portion 922 to reduce the risk of the mounting pin 906 rotatingwith respect to the lower support arm 920. This way, the coupling of theintegrated spring damper 800 to lower support arm 920 remains secure. Inresponse to the vehicle encountering an obstacle (e.g., a bump), theintegrated spring damper 800 may be configured to rotate with respect tothe lower support arm 920 because the ears 902 and 904 are notrestrictively coupled to the mounting pin 906.

As shown in FIG. 10C, when the mounting pin 906 is inserted into thepassage 924 of the mounting portion 922 and centered, first and secondends 926 and 928 of the mounting pin 906 protrude from the combinationof the mounting portion 922, seals 912, and thrust washers 914. Thefirst and second ends 926 and 928 provide connection points for the ears902 and 904 of the eyelet 820.

As shown in FIGS. 10D-10F, each thrust washer 914 includes an outersurface 918 and an inner ring 930. In one embodiment, there is adifference between the diameter of the inner ring 930 and the diameterof the mounting pin 906 to form an annular gap between the inner rings930 and the mounting pin 906. In one embodiment, the seals 912 aredisposed in these annular gaps. An outer surface of the seal 912 may beapproximately flush with an inner surface (e.g., opposite the outersurface 918 proximal the lower support arm 920) of the thrust washer914. Such a configuration facilitates the insertion of the combinationof the thrust washers 914 and seals 912 into the mounting portion 922 ofthe support arm 920. Additionally, the outer surfaces 918 may include aplurality of channels 932 therein. Portions of the seals 912 may bevisible when viewing the outer surfaces 918 of the thrust washers 914.The channels 932 facilitate the cleaning of the thrust washers 914 byproviding a conduit through which debris can be removed (e.g., manually,fall out of, automatically, etc.) from the thrust washers 914. Sincemore debris will tend flow through the channels 932, the debris will notremain on the surface of the thrust washers 914 and harden.

In the embodiment shown, the mounting portion 922 includes a firstsubstantially cylindrical passage 924. The mounting portion alsoincludes a second substantially cylindrical passage 934 on a first sideof the passage 924 and a third substantially cylindrical passage 936 ona second side of the passage 924. In one embodiment, the first passage924, the second passage 934, and the third passage 936 are concentric.The first passage 924 is of a first diameter and the second and thirdpassages 934 and 936 are of a second diameter that is greater than thefirst diameter. In one embodiment, the first passage 924 is centeredwithin the mounting portion 922 such that the second and third passages934 and 936 are of a similar dimension in the lengthwise direction ofthe mounting portion 922.

In one embodiment, the diameter of the first passage 924 is at leastequal to the diameter of the mounting pin 906. The diameters of thesecond and third passages 934 and 936 are at least equal to the diameterof the inner rings 930 of the thrust washers 914. In one embodiment, thecombinations of the thrust washers 914 and seals 912 are inserted intothe passages 934 and 936.

A first face 938 is disposed at the boundary between the first passage924 and the second passage 934, and a second face 940 is disposed at theboundary between the first passage 924 and the third passage 936. Axesnormal to the faces 938 and 940 point outward from the center of themounting portion 922. In one embodiment, the faces 928 and 940 include aplurality of grooves that are structured to receive portions of thethrust washers 914 and seals 912. Debris may be prevented from enteringthe first passage 924 and interfering with the coupling between themounting pin 906 and the mounting portion 922. In some embodiments,grooves in the faces 938 and 940 receive portions of the fasteners 916to secure the combinations of the seals 912 and thrusting washers 914 tothe mounting portion 922.

As shown in FIGS. 10G-10I, with the integrated spring damper 800 coupledto the mounting portion 922, surfaces of the ears 902 and 904 areapproximately flush with the outer surfaces 918 of the thrust washers914. Portions of the outer surfaces 918 of the thrust washers 914 extendoutwardly from the ears 902 and 904 of the eyelet 820, such thatportions of the outer surfaces 918 are at a larger radial position thanthe ears 902 and 904. Additionally, the inner rings 930 aresubstantially aligned with surfaces of the ears 902 and 904. As aresult, openings are formed at the channels 932 of the outer surfaces918. However, because the seals 912 fit in the gap between the innerrings 930 and the mounting pin 906, passage of debris through theseopenings is reduced (e.g., eliminated, etc.). Instead, the channelsguide the debris outwardly, away from the connection points between themounting pin 906 and the ears 902 and 904.

Referring now to FIGS. 11A-11B, isometric views of a main tube, shown asmain tube 942, and a cap, shown as cap 944, are shown in accordance withan example embodiment. In various embodiments, the main tube 942 may beequivalent to the main tube 816 discussed above. The cap 944 may be analternative to the cap 818 discussed above.

The cap 944 is affixed to a first end of the main tube 942. The cap 944includes an upper face 946 and a lower portion 948 that extends downwardfrom the upper face 946. In one embodiment, both the upper face 946 andthe lower portion 948 are substantially circular. The diameter of theupper face 946 may be greater than the diameter of the lower portion948. In one embodiment, the diameter of the lower portion 948 is at mostequal to an inner diameter of the main tube 942, and the lower portion948 may be coupled to an inner surface of the main tube 942 (e.g., witha threaded connection, etc.). In one embodiment, the diameter of thelower portion 948 is greater than an outer diameter of the main tube942, and the main tube 942 may be inserted into the lower portion 948.

In the embodiment shown, an annular groove 950 is formed proximate tothe center of the cap 944. Portions of an upper mount used to secure anintegrated spring damper to a vehicle may be inserted into the annulargroove 950. A substantially cylindrical protruding portion 945 extendsfrom the center of the upper face 946. In one embodiment, a frictionweld 952 is formed between the protruding portion 945 and a centralportion of the upper face 946. An opening 954 extends through theprotruding portion 945. In one embodiment, an additional opening 956extends through a central portion of the cap 944 to fluidly couple theprotruding portion 945 to the inner volume of the main tube 942 (e.g.,to form a pressure regulator for an integrated spring damper). In oneembodiment, the opening 954 is greater in diameter than the opening 956to increase the pressure of fluid being inserted into the main tube 942.

In the embodiment shown, the main tube 942 includes a first notch 958and a second notch 960 spaced from the first notch 958. In oneembodiment, the second notch 960 is disposed at an end of the main tube942 that is opposite to the cap 944. The spacing between the first notch958 and the second notch 960 may correspond to the distance betweenportions of a main piston (e.g., the main piston 824) of an integratedspring damper. The notches 958 and 960 facilitate the coupling of themain piston to the main tube 942 such that forces applied to the maintube 942 cause the positioning of the main piston to shift to providethe springing and damping forces discussed above.

Referring now to FIG. 12, a view of an integrated spring damper 1100 isshown, according to an exemplary embodiment. The integrated springdamper 1100 includes a main body, shown as main body 802, and a maintube, shown as main tube 942. The main body 802 is tubular. In oneembodiment, the main body 802 is manufactured using an extrusionprocess. In an alternative embodiment, the main body 802 is manufacturedusing a casting process. As shown in FIG. 12, a cap, shown as cap 804,and a barrier, shown as barrier 806, are disposed on opposing ends ofthe main body 802, defining an internal volume. The main tube 942 is atleast partially received within the internal volume of the main body802. The main tube 942 is configured to translate with respect to themain body 802. A cap, shown as cap 944, is disposed at a distal end ofthe main tube 942. The cap 804, barrier 806, and cap 944 may be coupledto the respective components with a threaded connection or with anothercoupling mechanism (e.g., welding, a friction weld, brazing,interference fit, etc.).

According to an exemplary embodiment, the integrated spring damper 1100includes a first mounting portion (e.g., a lower mounting portion,etc.), shown as eyelet 820, with which the integrated spring damper 1100is coupled to one portion of an axle assembly (e.g., a lower portion ofthe axle assembly, etc.). According to an exemplary embodiment, theintegrated spring damper 800 is coupled on one end (e.g., with theeyelet 820 on a lower end, etc.) to a moveable member of the axleassembly (e.g., a lower support arm, etc.). According to an exemplaryembodiment, the eyelet 820 is integrally formed with the cap 804. In oneembodiment, the eyelet 820 is coupled to a mounting portion (e.g., themounting portion 922) of a lower support arm (e.g., the lower supportarm 920) using a mounting pin (e.g., the mounting pin 906) discussedabove.

As shown in FIG. 12, the integrated spring damper 1100 includes a secondmounting portion (e.g., an upper mounting portion, a pin mount, etc.),shown as upper mount 964. The upper mount 964 is configured to couple anopposing second end (e.g., an upper end, etc.) of the integrated springdamper 1100 to a vehicle body, frame member, or part thereof.

In the embodiment shown, the upper mount 964 includes a first mountingmember 966 that is disposed proximal the cap 944. As shown in FIG. 12,the first mounting member 966 is inserted in an annular grove (e.g., theannular groove 950) in the cap 944. The first mounting member 966 issubstantially annular in shape and includes an opening through which aportion of the cap 844 extends. In one embodiment, the first mountingmember 966 is a resilient member, such as a flexible urethane, andserves as an isolator and an elastomeric spacer. In one embodiment, theupper surface of the first mounting member 966 is substantially flushwith an upper surface of a cap 944. In alternative embodiments, thefirst mounting member 966 extends above the upper surface of the cap944. The upper mount 964 further includes a second mounting member 968disposed proximal the first mounting member 966. In one embodiment, thesecond mounting member 968 may define a volume into which the cap 944 isdisposed. With the upper mount 964 disposed on the cap 944, the cap 944is substantially covered by the second mounting member 968. In oneembodiment, the second mounting member 968 is constructed of a metal oranother wear resistant material. In one embodiment, the first mountingmember 966 isolates the second mounting member 968 from the cap 944. Thefirst mounting member 966 may be friction welded to the second mountingmember 968. In one embodiment, the upper surface of the second mountingmember 968 is structured to abut the surface of a structure (e.g.,chassis, side plate, hull, etc.) of a vehicle.

The upper mount 964 further includes a third mounting member 970. Thethird mounting member 970 may be spaced from the second mounting member968 to provide space for a vehicle structure. The vehicle structure maybe mounted between the second portion 968 and the third mounting member970, such that a lower surface of the third mounting member abuts thevehicle structure. In one embodiment, the third mounting member 970 is aresilient member, such as a flexible urethane, and serves as an isolatorand an elastomeric spacer. The upper mount 964 further includes a fourthmounting member 972 disposed proximal the third mounting member 970. Thelower surface of the fourth mounting member 972 contacts the uppersurface of the third mounting member 970. In one embodiment, the fourthmounting member 972 is constructed from a metal or another wearresistant material. In one embodiment, the fourth mounting member 972 isfriction welded to the third mounting member 970.

In some embodiments, the first or second mounting members 966 and 968include portions that extend through an opening in the vehicle structure(e.g., a side wall) to which the integrated spring damper 1100 is to bemounted to engage with the third or fourth mounting members 970 and 972.

In the embodiment shown, each of the mounting members 966-972 issubstantially annular and include openings at approximately the centersthereof. In one embodiment, each of the openings receive the protrudingportion 945 of the cap 944. In one embodiment, the protruding portion945 of the cap 944 extends above the uppermost surface of the fourthmounting member 972 when the upper mount 964 is disposed on the cap 944.In one embodiment, an outer surface of the protruding portion 945 isthreaded such that a fastener 974 may be tightened to secure the uppermount 964, and thereby the integrated spring damper 1100, to a structureof a vehicle.

In one embodiment, a pressure regulation portion 976 may is coupled tothe fastener 974. The pressure regulation portion 976 may be coupled tothe openings in the protruding portion 845 of the cap to provide apressure regulation line for the integrated spring damper 1100. With thepressure regulation portion 976, compressible fluid may be introducedinto an internal volume of the main tube 942 to adjust the riding heightof the integrated spring damper 1100.

Referring now to FIGS. 13-15, an alternative secondary plunger 1326 isshown, according to various exemplary embodiments. The secondary plunger1326 may be used in place of any of the secondary plunger 626, thesecondary plunger 326, and/or the secondary plunger 526. The secondaryplunger 1326 may share features with either of the secondary plunger 526and the secondary plunger 626 (e.g., grooves on an inner surface 1333thereof and grooves on a contact surface thereof).

In the example shown in FIG. 13, an opposing surface 1329 (i.e., asurface of the secondary plunger 1326 that is opposite contact surface1327) includes grooves (e.g., kerfs, channels, recesses, gulleys,depressions, etc.), shown as a first surface groove 1302 a, a secondsurface groove 1302 b, a third surface groove 1302 c, a fourth surfacegroove 1302 d, a fifth surface groove 1302 e, a sixth surface groove1302 f, a seventh surface groove 1302 g, and an eighth surface groove1302 h. As shown in FIG. 13, each of the first surface groove 1302 a,the second surface groove 1302 b, the third surface groove 1302 c, thefourth surface groove 1302 d, the fifth surface groove 1302 e, the sixthsurface groove 1302 f, the seventh surface groove 1302 g, and the eighthsurface groove 1302 h (also referred to as surface grooves 1302) extendalong opposing surface 1329 at an angle relative a radial reference linepassing through its center (shown in greater detail below with referenceto FIG. 15A). Secondary plunger 1326 is shown including eight surfacegrooves 1302 (i.e., first surface groove 1302 a, second surface groove1302 b, third surface groove 1302 c, fourth surface groove 1302 d, fifthsurface groove 1302 e, sixth surface groove 1302 f, seventh surfacegroove 1302 g, and eighth surface groove 1302 h) extending outwardsalong opposing surface 1329, however secondary plunger 1326 may includeany number of surface grooves 1302, according to various exemplaryembodiments.

Referring still to FIGS. 13-15, secondary plunger 1326 is shown toinclude orifices (e.g., apertures, openings, cavities, mouths, holes,inlets, outlets, etc.), shown as bypass orifices 1332, according to anexemplary embodiment. Bypass orifices 1332 are adjacent to surfacegrooves 1302, thereby defining a shoulder between each bypass orifice1332 and surface groove 1302. The shoulder is shown filleted. In someembodiments, the shoulder is chamfered. Eight bypass orifices 1332 areshown with each of the bypass orifices 1332 corresponding to one ofsurface grooves 1302. For example, bypass orifice 1332 a corresponds tosurface groove 1302 a, bypass orifice 1332 b corresponds to surfacegroove 1302 b, bypass orifice 1332 c corresponds to surface groove 1302c, bypass orifice 1332 d corresponds to surface groove 1302 d, bypassorifice 1332 e corresponds to surface groove 1302 e, bypass orifice 1332f corresponds to surface groove 1302 f, bypass orifice 1332 gcorresponds to surface groove 1302 g, and bypass orifice 1332 hcorresponds to surface groove 1302 h. Each of bypass orifices 1332 maybe configured to facilitate a fluid flow path with the correspondingsurface groove 1302. For example, hydraulic fluid may flow along surfacegroove 1302 a, and then flow through the corresponding bypass orifice1332 a. In FIGS. 13-14, bypass orifices 1332 are shown extending throughan entire thickness of secondary plunger 1326 (e.g., extending fromopposing surface 1329 to contact surface 1327).

Referring to FIG. 15A, bypass orifices 1332 are shown defined as aportion of a circle 1514. In some embodiments, bypass orifices 1332 arearcuate, or generally curved. In some embodiments, bypass orifices 1332are defined by an arc having a non-constant radius of curvature.Specifically, bypass orifices 1332 are defined as portion of circle 1514defined by angle 1516. A center of circle 1514 is disposed a distance1502 radially outwards from a center 1520 of secondary plunger 1326. Insome embodiments, circle 1514 is disposed distance 1502 radiallyoutwards from center 1520 of secondary plunger 1326 and also offset adistance tangentially from an endpoint of distance 1502. Circle 1514 isshown having a radius 1512. Both the distance 1502 and the radius 1512of circle 1514 may determine an area 1522 which facilitates fluid flowtherethrough. For example, if distance 1502 increases, angle 1516increases, and area 1522 also increases, thereby facilitating more fluidto flow through area 1522. If radius 1512 increases, area 1522 alsoincreases, thereby facilitating more fluid to flow through area 1522. Inthis way, the radius 1512 and distance 1502 of circle 1514 from center1520 determine area 1522 and determine an amount of fluid which may passthrough bypass orifices 1332 therein (i.e., pass through area 1522). Theamount of fluid allowed to pass through bypass orifices 1332 maydetermine a damping amount when damper assembly 300 compresses. In thisway, area 1522 facilitates fluid flow and damping of damper assembly300.

Secondary plunger 1326 has inner radius 1506 and outer radius 1504,according to an exemplary embodiment. Inner radius 1506 is defined as adistance between center 1520 of secondary plunger 1326 and an innersurface 1333. Inner surface 1333 is defined as a surface facing radiallyinwards towards center 1520 of secondary plunger 1326. Outer radius 1504is defined as a distance between center 1520 of secondary plunger 1326and an outer periphery, shown as outer surface 1331 of secondary plunger1326. Outer surface 1331 and inner surface 1333 are substantiallycircular shaped, having radius 1504 and radius 1506, respectively. Insome embodiments, outer surface 1331 and inner surface 1333 are circularshaped and have coincident centers. Outer surface 1331 is shown facingradially outwards from center 1520 of secondary plunger 1326. Adifference between outer radius 1504 and inner radius 1506 may define aradial thickness 1510, according to some embodiments. In someembodiments, inner radius 1506 of inner surface 1333 is greater than anouter radius of shaft 338. In this way, a flow area is defined betweeninner surface 1333 and the outer radius of shaft 338. This areafacilitates the flow of hydraulic fluid through the space definedbetween inner surface 1333 and the outer radius of shaft 338. Increasinginner radius 1506 increases the area which facilitates hydraulic fluidtherethrough, thereby adjusting damping of damper assembly 300 (e.g., asdamper assembly 300 compresses).

Referring still to FIG. 15A, each of surface grooves 1302 are orientedat an angle. A centerline 1524 is shown extending radially outwards fromcenter 1520 of secondary plunger 1326. Centerline 1524 is shownextending through a center of a circle (not shown) which defines bypassorifice 1332 f. A centerline 1526 is shown extending along surfacegroove 1302 f from an end of centerline 1524 (e.g., where centerline1524 intersects bypass orifice 1332). In some embodiments, centerline1526 is not a centerline of surface groove 1302 f, but is still parallelto the centerline of surface groove 1302 f. Centerline 1526 andcenterline 1524 define an angle, shown as angle 1518. According to anexemplary embodiment, angle 1518 is 140 degrees. In some embodiments,angle 1518 is any value between 110 degrees and 160 degrees. In someembodiments, angle 1518 may be a negative value between −110 degrees and−160 degrees. In some embodiments, each of surface grooves 1302 areoriented at angle 1518, where each angle 1518 is defined similarly asdescribed herein with reference to surface groove 1302 f. In someembodiments, each of surface grooves 1302 are oriented at the same angle1518. In some embodiments, one or more of surface grooves 1302 areoriented at a first angle, while one or more surface grooves 1302 areoriented at a second angle. For example, the angle 1518 whichcorresponds to surface groove 1302 f may be 140 degrees, while the angle1518 which corresponds to surface groove 1302 a may be 120 degrees, etc.Surface grooves 1302 are shown having a width 1508. Width 1508 may be asame value for each of surface grooves 1302. In some embodiments, someof surface grooves 1302 have a first width 1508 while others of surfacegrooves 1302 have a second width 1508. For example, surface groove 1302a, surface groove 1302 c, surface groove 1302 e, and surface groove 1302g may have a first width 1508, while surface groove 1302 b, surfacegroove 1302 d, surface groove 1302 f, and surface groove 1302 h have asecond width 1508, according to some embodiments.

Referring to FIG. 15B, an alternative embodiment of secondary plunger1326 is shown according to an exemplary embodiment. Secondary plunger1326 includes surface groove 1304 a and surface groove 1304 b, disposedabout opposing surface 1329, and extending along opposing surface 1329.Surface groove 1304 a and surface groove 1304 b are disposedsymmetrically about secondary plunger 1326 relative to axis 1303. Axis1303 is shown parallel to both centerline 1306 and centerline 1308.Centerline 1306 and centerline 1308 are shown substantially parallel toeach other, and are each disposed an equal distance (normal to axis1303) from center 1520 of secondary plunger 1326. Surface groove 1304 aand surface groove 1304 b may have equal width, shown as width 1508.

Secondary plunger 1326 includes bypass orifice 1334 a and bypass orifice1334 b disposed along inner surface 1333 and within a correspondingsurface groove 1304. Each of the bypass orifices 1334 are associatedwith and adjacent to one of the surface grooves 1304. For example, asshown in FIG. 15B, bypass orifice 1334 a is adjacent to surface groove1304 a and bypass orifice 1334 b is adjacent to surface groove 1304 b.Bypass orifices 1334 may be generally arcuate and have a radius 1314.Bypass orifices 1334 are shown disposed a radial distance 1312 fromcenter 1520 and at angle 1316 relative to center 1520 and axis 1303.

Referring to FIG. 14, secondary plunger 1326 includes channels (i.e.,track, depression, kerf, notch, opening, recess, slit, etc.), shown aschannel 1318 and channel 1320, according to an exemplary embodiment. Asshown in FIG. 14, channel 1318 and channel 1320 extend along contactsurface 1327. Channel 1318 and channel 1320 extend radially outwardsfrom a center (e.g., center 1520 as shown in FIG. 15A) of secondaryplunger 1326. Channel 1318 and channel 1320 extend through an entireradial thickness of secondary plunger 1326 (e.g., radial thickness 1510as shown in FIG. 15A). In some embodiments, channel 1318 and channel1320 are configured to interface with one or more channels (i.e., track,depression, kerf, notch, opening, recess, slit, etc.) of plunger 312 tocooperatively form a channel. For example, plunger 312 may include oneor more channels extending radially outwards from a center of plunger312 and configured to interface with at least one of channel 1318 andchannel 1320 such that when plunger 312 moves into contact with contactsurface 1327, the one or more channels interface with at least one ofchannel 1318 and channel 1320 to form a bypass channel. Channel 1318 andchannel 1320 are shown having a rectangular cross-sectional area. Insome embodiments channel 1318 and channel 1320 have a non-rectangularcross-sectional area (e.g., circular, a portion of a circle, arcuate,etc.). Channel 1318 and channel 1320 are associated with and adjacent tobypass orifice 1332 a and bypass orifice 1332 e, respectively. In someembodiments, secondary plunger 1326 includes more than the two channels(i.e., channel 1318 and channel 1320). For example, each of bypassorifices 1332 may have a corresponding channel similar to channel 1318and channel 1320, according to some embodiments.

Referring again to FIG. 13, surface grooves 1302 are shown to have agenerally arc-shaped cross-sectional area. In other exemplaryembodiments, surface grooves 1302 may each have any othercross-sectional shape (e.g., rectangular). The number, size,orientation, and cross-sectional shape of surface grooves 1302 may bedetermined based on the flow characteristics that the surface grooves1302 produce. For example, if a particular flow characteristic isdesired (e.g., a specific damping), the number, size, orientation, andcross-sectional shape of surface grooves 1302 may be configured toachieve the desired flow characteristic. Additionally, bypass orifices1332 may be configured to achieve the desired flow characteristics. Forexample, as discussed above, the area 1522 may be changed by adjustingproperties of the bypass orifices 1332 (e.g., radius 1512, distance1502, etc.) to achieve the desired flow characteristics. As plunger 312moves into contact with contact surface 1327 (i.e., as damper 300extends), secondary plunger 1326 is forced to move such that recoilchamber 330 decreases in volume. As recoil chamber 330 decreases involume, hydraulic fluid present in recoil chamber 330 flows out ofrecoil chamber 330 and into compression chamber 342 or second chamber228. In order to flow from recoil chamber 330 to compression chamber342, the hydraulic fluid must flow through at least one of bypassorifices 1332 and at least one of channel 1318 and channel 1320. In someembodiments, fluid flows along at least one of surface grooves 1302before flowing through an adjacent bypass orifice 1332.

Advantageously, the size, number, and orientation of surface grooves1304 and surface grooves 1302 may prevent secondary plunger 1326 fromrotating while it is being driven by plunger 312. For example, as fluidpasses along surface grooves 1304, the fluid may apply a force to asurface of surface grooves 1304. The force applied to surface grooves1304 may generate a torque about a central axis 1310 (see FIG. 13),which may cause secondary plunger 1326 to rotate as secondary plungertravels due to plunger 312. Advantageously, the orientation (e.g., angle1518 of FIG. 15A) may be configured for some of surface grooves 1304such that some of surface grooves 1304 cause secondary plunger 1326 torotate in a first direction (e.g., clockwise), and other surface grooves1304 cause secondary plunger 1326 to rotate in a second direction (e.g.,counter-clockwise). In this way, a torque in the first direction due tosome of the surface grooves 1304 and a torque in the second directiondue to some of the surface grooves 1304 may be substantially equal andopposite such that secondary plunger 1326 is prevented from rotating.Surface grooves 1302 may result in similar or the same advantages bypreventing secondary plunger 1326 from rotating, similar to surfacegrooves 1304.

Referring now to FIG. 16, a portion of damper assembly 300 is shown,illustrating flow paths formed by plunger 312 and secondary plunger1326, according to an illustrative embodiment. As plunger 312 movesalong direction of travel 340, plunger 312 contacts and interfaces withcontact surface 1327 of secondary plunger 1326. After contacting andinterfacing with secondary plunger 1326, plunger 312 may continue tomove along direction of travel 340, moving secondary plunger 1326 alongdirection of travel 340 as well. Secondary plunger 1326 includesinterfacing member 328 (e.g., seal, ring, wear band, guide ring, wearring, etc.), disposed between annular groove 1330 of secondary plunger1326 and an interior surface of housing 314, therein preventing fluidfrom flowing between an outer surface of secondary plunger 1326 and theinterior surface of housing 314. As secondary plunger 1326 moves alongdirection of travel 340, recoil chamber 330 decreases in volume andcompression chamber 342 increases in volume, with fluid flowing out ofrecoil chamber 330 and into compression chamber 342 or second chamber228. Fluid may flow between recoil chamber 330 and compression chamber342 along flow path 1608 and flow path 1610. Flow path 1608 is formed bysurface groove 1302 a, bypass orifice 1332 a, and channel 1318 ofsecondary plunger 1326. In some embodiments, plunger 312 includes agroove (i.e., track, channel, depression, kerf, notch, opening, recess,slit, etc.), shown as first groove 1604, which cooperatively forms flowpath 1608 by interfacing with at least one of bypass orifice 1332 a andchannel 1318. In some embodiments, plunger 312 does not include firstgroove 1604, and flow path 1608 is formed without first groove 1604.Flow path 1610 is similarly formed by surface groove 1302 e, bypassorifice 1332 e, and channel 1320 of secondary plunger 1326. In someembodiments, plunger 312 includes a second groove (i.e., track, channel,depression, kerf, notch, opening, recess, slit, etc.), shown as secondgroove 1606, which cooperatively forms flow path 1610 by interfacingwith at least one of bypass orifice 1332 e and channel 1320. In someembodiments, plunger 312 does not include second groove 1606, and flowpath 1610 is formed without second groove 1606.

Referring still to FIG. 16, fluid may flow along flow path 1608 and/orflow path 1610. Some of the fluid from recoil chamber 330 may flow alongflow path 1608 and/or flow path 1610 without flowing along eithersurface groove 1302 a or surface groove 1302 e. For example, some of thefluid of recoil chamber 330 may flow through area 1522 of bypass orifice1332 a and into compression chamber 342 or second chamber 228 throughchannel 1318 without flowing along surface groove 1302 a. FIG. 16 showsinner radius 1506 of secondary plunger 1326 being substantially equal toradius 1609 of shaft 338. In some embodiments, inner radius 1506 ofsecondary plunger 1326 is substantially larger than radius 1609 of shaft338, allowing an additional area for fluid to flow therein.

Referring now to FIGS. 17-19, several configurations of damper assembly300 are shown, as damper assembly 300 extends (e.g., recoils), accordingto an exemplary embodiment. FIG. 17 shows damper assembly 300 withplunger 312 shown not yet in contact with secondary plunger 1326. Damperassembly 300 is shown to include recoil chamber 330, extension chamber318 and compression chamber 342. In the configuration shown in FIG. 17,extension chamber 318 is defined as a volume between plunger 312 andsecondary plunger 1326 and within housing 314. As plunger 312 movesalong direction of travel 340, extension chamber 318 decreases involume. Plunger 312 may move along direction of travel 340 until itinterfaces with secondary plunger 1326. Secondary plunger 1326 is shownadjacent step 344. In some embodiments, secondary plunger 1326 is biasinto engagement with step 344 by return spring 334.

Referring now to FIGS. 18 and 19, plunger 312 is shown moved to aposition where plunger 312 engages with secondary plunger 1326. Asdiscussed above with reference to FIG. 17, secondary plunger 1326 may beadjacent step 344. When plunger 312 moves along direction of travel 340and reaches the position where step 344 is, plunger engages withsecondary plunger 1326. When plunger 312 engages with secondary plunger1326 the volume of extension chamber 318 may be substantially zero.Plunger 312 and secondary plunger 1326 cooperatively form flow path 1608and flow path 1610 through the interface between plunger 312 andsecondary plunger 1326. Flow path 1608 is defined by bypass orifice1332, channel 1320, and plunger 312. In some embodiments, flow path 1608is also defined by surface groove 1302. Flow path 1610 may be formedsimilarly to flow path 1608. Flow path 1608 and flow path 1610 allowfluid to flow between recoil chamber 330 and extension chamber 342 assecondary plunger 1326 moves along direction of travel 340 (e.g., beingdriven to move along direction of travel 340 by plunger 312). In someembodiments, fluid cannot flow between recoil chamber 330 and extensionchamber 342 through flow path 1608 and flow path 1610 until damper 312has moved a distance along direction of travel 340 such that an outerperiphery of plunger 312 is no longer interfaced with an inner surfaceof the second portion of housing 314. After damper 312 has moved alongdirection of travel 340 such that plunger 312 is no longer interfacedwith the inner surface of the second portion of housing 314, flow path1608 and flow path 1610 may allow fluid to flow between recoil chamber330 and extension chamber 342.

Referring to FIG. 19, plunger 312 and secondary plunger 1326 are shownmoved to an extremum position along direction of travel 340. In theconfiguration shown in FIG. 19, recoil chamber 330 may have a volumesubstantially equal to zero, with substantially all of the fluid ofrecoil chamber 330 having entered compression chamber 342. As plunger312 and secondary plunger 1326 move along direction of travel 340between the configuration shown in FIG. 18 and the configuration shownin FIG. 19, flow path 1608 and flow path 1610 may be additionally formedby a difference between an outer periphery of plunger 312 and the firstdiameter of the first portion of housing 314. Fluid may flow between theouter periphery of plunger 312 and first portion of housing 314.

As plunger 312 and secondary plunger 1326 move along direction of travel340 and fluid flows from recoil chamber 330 to compression chamber 342,secondary plunger 1326 may provide additional damping. The damping maybe determined based on a restriction to the flow of fluid between recoilchamber 330 and compression chamber 342 provided by any of bypassorifices 1332 (or bypass orifices 1334), and channel 1320 and channel1318 which cooperatively form flow path 1608 and flow path 1610 withplunger 312. Bypass orifices 1332, bypass orifices 1334, channel 1320and channel 1318 may be configured to restrict fluid flow along any offlow path 1608 and flow path 1610 to provide an additional damping forceproportional to the pressure difference between the fluids in each ofrecoil chamber 330 and compression chamber 342. Thus, through such aconfiguration, the secondary plunger 1326 provides an additional dampingforce when the pressure differences are greatest (e.g., when the damperassembly 300 is at the end of a stroke, when the secondary plunger 1326and plunger 312 approach the configuration shown in FIG. 19).

Referring now to FIGS. 20-21, top sectional views of damper assembly 300in the configuration shown in either FIG. 18 or FIG. 19 are shown,according to an exemplary embodiment.

As utilized herein, the terms “approximately”, “about”, “substantially”,and similar terms are intended to have a broad meaning in harmony withthe common and accepted usage by those of ordinary skill in the art towhich the subject matter of this disclosure pertains. It should beunderstood by those of skill in the art who review this disclosure thatthese terms are intended to allow a description of certain featuresdescribed and claimed without restricting the scope of these features tothe precise numerical ranges provided. Accordingly, these terms shouldbe interpreted as indicating that insubstantial or inconsequentialmodifications or alterations of the subject matter described and claimedare considered to be within the scope of the invention as recited in theappended claim.

It should be noted that the terms “exemplary” and “example” as usedherein to describe various embodiments is intended to indicate that suchembodiments are possible examples, representations, and/or illustrationsof possible embodiments (and such term is not intended to connote thatsuch embodiments are necessarily extraordinary or superlative examples).

The terms “coupled,” “connected,” and the like, as used herein, mean thejoining of two members directly or indirectly to one another. Suchjoining may be stationary (e.g., permanent, etc.) or moveable (e.g.,removable, releasable, etc.). Such joining may be achieved with the twomembers or the two members and any additional intermediate members beingintegrally formed as a single unitary body with one another or with thetwo members or the two members and any additional intermediate membersbeing attached to one another.

References herein to the positions of elements (e.g., “top,” “bottom,”“above,” “below,” “between,” etc.) are merely used to describe theorientation of various elements in the figures. It should be noted thatthe orientation of various elements may differ according to otherexemplary embodiments, and that such variations are intended to beencompassed by the present disclosure.

Also, the term “or” is used in its inclusive sense (and not in itsexclusive sense) so that when used, for example, to connect a list ofelements, the term “or” means one, some, or all of the elements in thelist. Conjunctive language such as the phrase “at least one of X, Y, andZ,” unless specifically stated otherwise, is otherwise understood withthe context as used in general to convey that an item, term, etc. may beeither X, Y, Z, X and Y, X and Z, Y and Z, or X, Y, and Z (i.e., anycombination of X, Y, and Z). Thus, such conjunctive language is notgenerally intended to imply that certain embodiments require at leastone of X, at least one of Y, and at least one of Z to each be present,unless otherwise indicated.

It is important to note that the construction and arrangement of thesystems as shown in the exemplary embodiments is illustrative only.Although only a few embodiments of the present disclosure have beendescribed in detail, those skilled in the art who review this disclosurewill readily appreciate that many modifications are possible (e.g.,variations in sizes, dimensions, structures, shapes and proportions ofthe various elements, values of parameters, mounting arrangements, useof materials, colors, orientations, etc.) without materially departingfrom the novel teachings and advantages of the subject matter recited.For example, elements shown as integrally formed may be constructed ofmultiple parts or elements. It should be noted that the elements and/orassemblies of the components described herein may be constructed fromany of a wide variety of materials that provide sufficient strength ordurability, in any of a wide variety of colors, textures, andcombinations. Accordingly, all such modifications are intended to beincluded within the scope of the present inventions. Othersubstitutions, modifications, changes, and omissions may be made in thedesign, operating conditions, and arrangement of the preferred and otherexemplary embodiments without departing from scope of the presentdisclosure or from the spirit of the appended claim.

What is claimed is:
 1. A damper assembly, comprising: a tubular memberincluding a sidewall and a cap at an end of the sidewall, the sidewalland the cap defining an inner volume, wherein the sidewall comprises afirst portion and a second portion, wherein the first portion and thesecond portion define a shoulder; a rod extending within the innervolume; a primary piston positioned within the inner volume and coupledto the rod, the primary piston defining a first contact surface; asecondary piston comprising: a body member comprising a second contactsurface, an opposing second surface, an inner cylindrical face defininga central aperture that receives the rod, and an outer cylindrical face,wherein the opposing second surface comprises one or more surfacegrooves disposed about the body member, extending across an entireradial width of the opposing second surface from the inner cylindricalface to the outer cylindrical face; one or more bypass orifices disposedabout the body member, wherein the one or more bypass orifices extendalong the inner cylindrical face between the second contact surface andthe opposing second surface; wherein the secondary piston defines achannel extending between the inner cylindrical face and an outerperiphery of the body member, wherein the primary piston and thesecondary piston separate the inner volume into a first working chamber,a second working chamber, and a recoil chamber; a resilient memberdisposed between the secondary piston and the cap and thereby positionedto bias the secondary piston into engagement with the shoulder; whereinthe first contact surface and the channel are configured tocooperatively define a flow conduit upon engagement between the primarypiston and the secondary piston; wherein the second contact surface isconfigured to engage the first contact surface such that an open flowpath is formed from the recoil chamber through the central aperture andthe flow conduit upon engagement between the primary piston and thesecondary piston.
 2. The damper assembly of claim 1, wherein the primarypiston is moveable within the tubular member between a first location,an intermediate location, and an end of stroke, and wherein the primarypiston is configured to maintain engagement with the secondary pistonbetween the intermediate location and the end of stroke.
 3. The damperassembly of claim 1, wherein the recoil chamber is defined between theopposing second surface of the secondary piston and the cap.
 4. Thedamper assembly of claim 1, wherein one or more of the one or moresurface grooves are angled relative to a centerline extending radiallyoutwards from a center of the secondary piston.
 5. The damper assemblyof claim 4, wherein one or more of the one or more surface grooves areat an angle between 110 and 160 degrees relative to the centerlineextending radially outwards from the center of the secondary plunger. 6.The damper assembly of claim 5, wherein the first portion has a firstdiameter and the second portion has a second diameter, wherein the firstdiameter is greater than the second diameter, and wherein the transitionbetween the first portion and the second portion defines the shoulder.7. The damper assembly of claim 6, wherein the diameter of the primarypiston is less than the second diameter such that the primary piston isextendable along the length of the tubular member.
 8. The damperassembly of claim 1, wherein each of the one or more bypass orifices areadjacent to one of the one or more surface grooves.
 9. A damperassembly, comprising: a housing having an end cap and defining an innervolume, wherein the housing includes a first portion and a secondportion, wherein the transition between the first portion and the secondportion defines a shoulder; a primary piston positioned within thehousing; and a limiter positioned between the primary piston and the endcap, the limiter comprising a damper piston comprising a body memberhaving: a contact surface; an inner cylindrical face that defines anaperture through a central portion of the body member; an outercylindrical face; an opposing second surface, wherein the opposingsecond surface comprises one or more surface grooves disposed about thebody member, extending across an entire radial width of the opposingsecond surface from the inner cylindrical face to the outer cylindricalface; one or more bypass orifices disposed about the body member,wherein the one or more bypass orifices extend along the innercylindrical face between the second contact surface and the opposingsecond surface; wherein the primary piston and the damper pistonseparate the inner volume into a first working chamber, a second workingchamber, and a recoil chamber; a resilient member disposed within therecoil chamber, between the opposing second surface of the damper pistonand the end cap, the resilient member thereby positioned to bias thedamper piston into engagement with the shoulder; and a rod coupled tothe primary piston and extending through the aperture defined by thedamper piston; wherein the damper piston defines a channel extendinglaterally outward from the inner cylindrical face across the contactsurface to an outer periphery of the body member, wherein the primarypiston and the channel are configured to cooperatively define a firstflow conduit upon engagement between the primary piston and the damperpiston; and wherein an outer surface of the rod and the innercylindrical face of the damper piston define a second flow conduit, andwherein the first flow conduit and the second flow conduit cooperate todefine an open flow path from the recoil chamber.
 10. The damperassembly of claim 9, wherein the primary piston, the first portion, andthe second portion have circular cross-sectional shapes.
 11. The damperassembly of claim 10, wherein the first portion has a first diameter andthe second portion has a second diameter, wherein the first diameter isgreater than the second diameter, and wherein the transition between thefirst portion and the second portion defines the shoulder.
 12. Thedamper assembly of claim 11, wherein the diameter of the primary pistonis less than the second diameter such that the primary piston isextendable along the length of the housing.
 13. The damper assembly ofclaim 12, wherein the primary piston and the housing cooperativelydefine a space around an outer periphery of the primary piston therebyproviding a flow path around the outer periphery of the primary piston.14. The damper assembly of claim 9, wherein each of the one or morebypass orifices are adjacent to one of the one or more surface grooves.15. The damper assembly of claim 9, wherein the primary piston ismoveable within the housing between a first location, an intermediatelocation, and an end of stroke, and wherein the primary piston isconfigured to maintain engagement with the limiter between theintermediate location and the end of stroke.
 16. The damper assembly ofclaim 9, wherein one or more of the one or more surface grooves areangled relative to a centerline extending radially outwards from acenter of the damper piston.
 17. The damper assembly of claim 16,wherein one or more of the one or more surface grooves are at an anglebetween 110 and 160 degrees relative to the centerline extendingradially outwards from the center of the damper piston.
 18. The damperassembly of claim 9, wherein the recoil chamber is defined between theopposing second surface of the damper piston and the end cap.
 19. Adamper assembly, comprising: a housing having an end cap, the housingand the end cap defining an inner volume, wherein the housing comprisesa first portion and a second portion, wherein the first portion and thesecond portion define a shoulder; a primary piston positioned within thehousing; a limiter positioned between the primary piston and the endcap, the limiter comprising a damper piston including a body memberhaving: a contact surface; an inner cylindrical face that defines anaperture through a central portion of the body member; an outercylindrical face; an opposing second surface, wherein the opposingsecond surface comprises one or more surface grooves disposed about thebody member, extending across an entire radial width of the opposingsecond surface from the inner cylindrical face to the outer cylindricalface; and one or more bypass orifices circumferentially disposed aboutthe body member, wherein the one or more bypass orifices extend alongthe inner cylindrical face between the contact surface and the opposingsecond surface; wherein the primary piston and the damper pistonseparate the inner volume into a first working chamber, a second workingchamber, and a recoil chamber; a rod coupled to the primary piston andextending through the aperture defined by the damper piston; wherein thedamper piston defines: a first channel extending laterally outward fromthe inner cylindrical face across the contact surface to an outerperiphery of the body member; and an second channel within the innercylindrical face between the contact surface and the opposing secondsurface; wherein the primary piston and the first channel are configuredto cooperatively define a flow conduit upon engagement between theprimary piston and the damper piston; and wherein the flow conduit andthe second channel cooperate to define an open flow path from the recoilchamber.
 20. The damper assembly of claim 19, wherein at least one ofthe one or more bypass orifices and the first channel cooperativelydefine a flow path from the recoil chamber.